diff --git a/app/controllers/debates_controller.rb b/app/controllers/debates_controller.rb
index 1c5696304..7b6dc8fa1 100644
--- a/app/controllers/debates_controller.rb
+++ b/app/controllers/debates_controller.rb
@@ -21,8 +21,8 @@ class DebatesController < ApplicationController
     @root_comments = @debate.comments.roots.recent.page(params[:page]).per(10).for_render
     @comments = @root_comments.inject([]){|all, root| all + root.descendants}
 
-    all_visible_comments = @root_comments + @comments
-    set_comment_flags(all_visible_comments)
+    @all_visible_comments = @root_comments + @comments
+    set_comment_flags(@all_visible_comments)
   end
 
   def new
diff --git a/app/helpers/cache_keys_helper.rb b/app/helpers/cache_keys_helper.rb
index 38445ae02..f75a21a59 100644
--- a/app/helpers/cache_keys_helper.rb
+++ b/app/helpers/cache_keys_helper.rb
@@ -12,6 +12,8 @@ module CacheKeysHelper
       user_status += ":signed"
       user_status += ":verified" if current_user.verified_at.present?
       user_status += ":org" if current_user.organization?
+      user_status += ":admin" if current_user.administrator?
+      user_status += ":moderator" if current_user.moderator?
     else
       user_status += ":visitor"
     end
diff --git a/app/models/administrator.rb b/app/models/administrator.rb
index 15715a328..8a34fa349 100644
--- a/app/models/administrator.rb
+++ b/app/models/administrator.rb
@@ -1,5 +1,5 @@
 class Administrator < ActiveRecord::Base
-  belongs_to :user
+  belongs_to :user, touch: true
   delegate :name, :email, to: :user
 
   validates :user_id, presence: true, uniqueness: true
diff --git a/app/models/comment.rb b/app/models/comment.rb
index 8dd922714..efa9ec7a0 100644
--- a/app/models/comment.rb
+++ b/app/models/comment.rb
@@ -13,7 +13,7 @@ class Comment < ActiveRecord::Base
   belongs_to :commentable, -> { with_hidden }, polymorphic: true, counter_cache: true
   belongs_to :user, -> { with_hidden }
 
-  has_many :flags, :as => :flaggable
+  has_many :flags, as: :flaggable
 
   scope :recent, -> { order(id: :desc) }
 
diff --git a/app/models/debate.rb b/app/models/debate.rb
index 8471be20d..5e2864767 100644
--- a/app/models/debate.rb
+++ b/app/models/debate.rb
@@ -9,8 +9,8 @@ class Debate < ActiveRecord::Base
   include ActsAsParanoidAliases
 
   belongs_to :author, -> { with_hidden }, class_name: 'User', foreign_key: 'author_id'
-  has_many :flags, :as => :flaggable
   has_many :comments, as: :commentable
+  has_many :flags, as: :flaggable
 
   validates :title, presence: true
   validates :description, presence: true
diff --git a/app/models/flag.rb b/app/models/flag.rb
index 2d13d26d9..02b16b385 100644
--- a/app/models/flag.rb
+++ b/app/models/flag.rb
@@ -22,6 +22,7 @@ class Flag < ActiveRecord::Base
   end
 
   def self.flagged?(user, flaggable)
+    return false unless user
     !! by_user_and_flaggable(user, flaggable).try(:first)
   end
 
diff --git a/app/models/moderator.rb b/app/models/moderator.rb
index 30d4f4394..6a5af7a52 100644
--- a/app/models/moderator.rb
+++ b/app/models/moderator.rb
@@ -1,5 +1,5 @@
 class Moderator < ActiveRecord::Base
-  belongs_to :user
+  belongs_to :user, touch: true
   delegate :name, :email, to: :user
 
   validates :user_id, presence: true, uniqueness: true
diff --git a/app/models/organization.rb b/app/models/organization.rb
index fa991fc05..2962724a6 100644
--- a/app/models/organization.rb
+++ b/app/models/organization.rb
@@ -1,5 +1,5 @@
 class Organization < ActiveRecord::Base
-  belongs_to :user
+  belongs_to :user, touch: true
 
   validates :name, presence: true
 
diff --git a/app/models/user.rb b/app/models/user.rb
index 71db4ee2e..0ae4d3290 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -36,6 +36,17 @@ class User < ActiveRecord::Base
   scope :officials,      -> { where("official_level > 0") }
   scope :for_render,     -> { includes(:organization) }
 
+  after_update :touch_debates, :touch_comments
+  after_touch :touch_debates, :touch_comments
+
+  def touch_debates
+    debates.map(&:touch)
+  end
+
+  def touch_comments
+    comments.map(&:touch)
+  end
+
   def self.find_for_oauth(auth, signed_in_resource = nil)
     # Get the identity and user if they exist
     identity = Identity.find_for_oauth(auth)
diff --git a/app/views/comments/_comment.html.erb b/app/views/comments/_comment.html.erb
index 3ee61e9f4..8bf07a8b3 100644
--- a/app/views/comments/_comment.html.erb
+++ b/app/views/comments/_comment.html.erb
@@ -1,101 +1,104 @@
-<div class="row">
-	<div id="<%= dom_id(comment) %>" class="comment small-12 column">
+<% cache [locale_and_user_status, comment, @commentable, Flag.flagged?(current_user, comment)] do %>
+  <div class="row">
+  	<div id="<%= dom_id(comment) %>" class="comment small-12 column">
 
-    <% if comment.hidden? || comment.user.hidden? %>
-      <% if select_children(@comments, comment).size > 0 %>
-        <div class="is-deleted">
-          <p><%= t("debates.comment.deleted") %></p>
-        </div>
-      <% end %>
-    <% else %>
-      <% if comment.as_administrator? %>
-        <%= image_tag("admin_avatar.png", size: 32, class: "admin-avatar left") %>
-      <% elsif comment.as_moderator? %>
-        <%= image_tag("moderator_avatar.png", size: 32, class: "moderator-avatar left") %>
+      <% if comment.hidden? || comment.user.hidden? %>
+        <% if select_children(@comments, comment).size > 0 %>
+          <div class="is-deleted">
+            <p><%= t("debates.comment.deleted") %></p>
+          </div>
+        <% end %>
       <% else %>
-        <% if comment.user.organization? %>
-          <%= image_tag("collective_avatar.png", size: 32, class: "avatar left") %>
+        <% if comment.as_administrator? %>
+          <%= image_tag("admin_avatar.png", size: 32, class: "admin-avatar left") %>
+        <% elsif comment.as_moderator? %>
+          <%= image_tag("moderator_avatar.png", size: 32, class: "moderator-avatar left") %>
         <% else %>
-          <%= avatar_image(comment.user, seed: comment.user_id, size: 32, class: "left") %>
-        <% end %>
-        <% if comment.user.hidden? %>
-          <i class="icon-deleted user-deleted"></i>
-        <% end %>
-      <% end %>
-
-      <div class="comment-body">
-        <div class="comment-info">
-
-          <% if comment.as_administrator? %>
-            <span class="user-name"><%= t("debates.comment.admin") %> #<%= comment.administrator_id%></span>
-          <% elsif comment.as_moderator? %>
-            <span class="user-name"><%= t("debates.comment.moderator") %> #<%= comment.moderator_id%></span>
+          <% if comment.user.organization? %>
+            <%= image_tag("collective_avatar.png", size: 32, class: "avatar left") %>
           <% else %>
+            <%= avatar_image(comment.user, seed: comment.user_id, size: 32, class: "left") %>
+          <% end %>
+          <% if comment.user.hidden? %>
+            <i class="icon-deleted user-deleted"></i>
+          <% end %>
+        <% end %>
 
-            <% if comment.user.hidden? %>
-              <span class="user-name"><%= t("debates.comment.user_deleted") %></span>
+        <div class="comment-body">
+          <div class="comment-info">
+
+            <% if comment.as_administrator? %>
+              <span class="user-name"><%= t("debates.comment.admin") %> #<%= comment.administrator_id%></span>
+            <% elsif comment.as_moderator? %>
+              <span class="user-name"><%= t("debates.comment.moderator") %> #<%= comment.moderator_id%></span>
             <% else %>
-              <span class="user-name"><%= comment.user.name %></span>
-              <% if comment.user.official? %>
+
+              <% if comment.user.hidden? %>
+                <span class="user-name"><%= t("debates.comment.user_deleted") %></span>
+              <% else %>
+                <span class="user-name"><%= comment.user.name %></span>
+                <% if comment.user.official? %>
+                  &nbsp;&bullet;&nbsp;
+                  <span class="label round level-<%= comment.user.official_level %>">
+                    <%= comment.user.official_position %>
+                  </span>
+                <% end %>
+              <% end %>
+              <% if comment.user.verified_organization? %>
                 &nbsp;&bullet;&nbsp;
-                <span class="label round level-<%= comment.user.official_level %>">
-                  <%= comment.user.official_position %>
+                <span class="label round is-association">
+                  <%= t("shared.collective") %>
                 </span>
               <% end %>
-            <% end %>
-            <% if comment.user.verified_organization? %>
-              &nbsp;&bullet;&nbsp;
-              <span class="label round is-association">
-                <%= t("shared.collective") %>
-              </span>
-            <% end %>
-            <% if comment.user_id == @commentable.author_id %>
-              &nbsp;&bullet;&nbsp;
-              <span class="label round is-author">
-                <%= t("debates.comment.author") %>
-              </span>
+              <% if comment.user_id == @commentable.author_id %>
+                &nbsp;&bullet;&nbsp;
+                <span class="label round is-author">
+                  <%= t("debates.comment.author") %>
+                </span>
+              <% end %>
+
             <% end %>
 
+            &nbsp;&bullet;&nbsp;<%= time_ago_in_words(comment.created_at) %>
+          </div>
+
+          <% if comment.as_administrator? %>
+            <p class="comment-user is-admin"><%= comment.body %></p>
+          <% elsif comment.as_moderator? %>
+            <p class="comment-user is-moderator"><%= comment.body %></p>
+          <% elsif comment.user.official? && comment.user_id == @commentable.author_id %>
+            <p class="comment-user level-<%= comment.user.official_level %> is-author"><%= comment.body %></p>
+          <% elsif comment.user.official? %>
+            <p class="comment-user level-<%= comment.user.official_level %>"><%= comment.body %></p>
+          <% elsif comment.user_id == @commentable.author_id %>
+            <p class="comment-user is-author"><%= comment.body %></p>
+          <% else %>
+            <p class="comment-user"><%= comment.body %></p>
           <% end %>
+          <span id="<%= dom_id(comment) %>_votes" class="comment-votes right">
+            <%= render 'comments/votes', comment: comment %>
+          </span>
 
-          &nbsp;&bullet;&nbsp;<%= time_ago_in_words(comment.created_at) %>
+          <div class="reply">
+            <%= t("debates.comment.responses", count: select_children(@comments, comment).size) %>
+
+            <% if user_signed_in? %>
+              <span class="divider">&nbsp;|&nbsp;</span>
+              <%= link_to(comment_link_text(comment), "",
+                          class: "js-add-comment-link", data: {'id': dom_id(comment)}) %>
+
+              <%= render 'comments/actions', comment: comment %>
+
+              <%= render 'comments/form', {commentable: @commentable, parent_id: comment.id, toggeable: true} %>
+            <% end %>
+          </div>
         </div>
-
-        <% if comment.as_administrator? %>
-          <p class="comment-user is-admin"><%= comment.body %></p>
-        <% elsif comment.as_moderator? %>
-          <p class="comment-user is-moderator"><%= comment.body %></p>
-        <% elsif comment.user.official? && comment.user_id == @commentable.author_id %>
-          <p class="comment-user level-<%= comment.user.official_level %> is-author"><%= comment.body %></p>
-        <% elsif comment.user.official? %>
-          <p class="comment-user level-<%= comment.user.official_level %>"><%= comment.body %></p>
-        <% elsif comment.user_id == @commentable.author_id %>
-          <p class="comment-user is-author"><%= comment.body %></p>
-        <% else %>
-          <p class="comment-user"><%= comment.body %></p>
-        <% end %>
-        <span id="<%= dom_id(comment) %>_votes" class="comment-votes right">
-          <%= render 'comments/votes', comment: comment %>
-        </span>
-
-        <div class="reply">
-          <%= t("debates.comment.responses", count: select_children(@comments, comment).size) %>
-
-          <% if user_signed_in? %>
-            <span class="divider">&nbsp;|&nbsp;</span>
-            <%= link_to(comment_link_text(comment), "",
-                        class: "js-add-comment-link", data: {'id': dom_id(comment)}) %>
-
-            <%= render 'comments/actions', comment: comment %>
-
-            <%= render 'comments/form', {commentable: @commentable, parent_id: comment.id, toggeable: true} %>
-          <% end %>
-        </div>
-      </div>
-    <% end %>
-
+      <% end %>
+<% end %>
     <div class="comment-children">
-      <%= render select_children(@comments, comment) if @comments.present? %>
+      <% select_children(@comments, comment).each do |child| %>
+        <%= render 'comments/comment', comment: child %>
+      <% end %>
     </div>
   </div>
-</div>
+</div>
\ No newline at end of file
diff --git a/app/views/comments/_form.html.erb b/app/views/comments/_form.html.erb
index 9a7d26554..eb2507136 100644
--- a/app/views/comments/_form.html.erb
+++ b/app/views/comments/_form.html.erb
@@ -1,25 +1,28 @@
 <% css_id = parent_or_commentable_dom_id(parent_id, commentable) %>
-<div id="js-comment-form-<%= css_id %>" <%= "style='display:none'".html_safe if toggeable %>>
-  <%= form_for [commentable, Comment.new], remote: true do |f| %>
-    <%= label_tag "comment-body-#{css_id}", t("comments.form.leave_comment") %>
-    <%= f.text_area :body, id: "comment-body-#{css_id}", label: false %>
-    <%= f.hidden_field :commentable_type, value: commentable.class.name %>
-    <%= f.hidden_field :commentable_id, value: commentable.id %>
-    <%= f.hidden_field :parent_id, value: parent_id %>
+<% cache [locale_and_user_status, css_id] do %>
+  <div id="js-comment-form-<%= css_id %>" <%= "style='display:none'".html_safe if toggeable %>>
+    <%= form_for [commentable, Comment.new], remote: true do |f| %>
+      <%= label_tag "comment-body-#{css_id}", t("comments.form.leave_comment") %>
+      <%= f.text_area :body, id: "comment-body-#{css_id}", label: false %>
+      <%= f.hidden_field :commentable_type, value: commentable.class.name %>
+      <%= f.hidden_field :commentable_id, value: commentable.id %>
+      <%= f.hidden_field :parent_id, value: parent_id %>
 
-    <%= f.submit comment_button_text(parent_id), class: "button radius small inline-block" %>
+      <%= f.submit comment_button_text(parent_id), class: "button radius small inline-block" %>
+
+      <% if can? :comment_as_moderator, commentable %>º
+        <div class="right">
+          <%= f.check_box :as_moderator, id: "comment-as-moderator-#{css_id}", label: false %>
+          <%= label_tag "comment-as-moderator-#{css_id}", t("comments.form.comment_as_moderator"), class: "checkbox" %>
+        </div>
+      <% end %>
+      <% if can? :comment_as_administrator, commentable %>
+        <div class="right">
+          <%= f.check_box :as_administrator, id: "comment-as-administrator-#{css_id}",label: false %>
+          <%= label_tag "comment-as-administrator-#{css_id}", t("comments.form.comment_as_admin"), class: "checkbox" %>
+        </div>
+      <% end %>
 
-    <% if can? :comment_as_moderator, commentable %>º
-      <div class="right">
-        <%= f.check_box :as_moderator, id: "comment-as-moderator-#{css_id}", label: false %>
-        <%= label_tag "comment-as-moderator-#{css_id}", t("comments.form.comment_as_moderator"), class: "checkbox" %>
-      </div>
     <% end %>
-    <% if can? :comment_as_administrator, commentable %>
-      <div class="right">
-        <%= f.check_box :as_administrator, id: "comment-as-administrator-#{css_id}",label: false %>
-        <%= label_tag "comment-as-administrator-#{css_id}", t("comments.form.comment_as_admin"), class: "checkbox" %>
-      </div>
-    <% end %>
-  <% end %>
-</div>
+  </div>
+<% end %>
\ No newline at end of file
diff --git a/app/views/debates/_comments.html.erb b/app/views/debates/_comments.html.erb
new file mode 100644
index 000000000..39ed635ba
--- /dev/null
+++ b/app/views/debates/_comments.html.erb
@@ -0,0 +1,30 @@
+<% cache [locale_and_user_status, @all_visible_comments.map(&:cache_key), @debate.comments_count, @comment_flags.to_a] do %>
+  <section class="row-full comments">
+    <div class="row">
+      <div id="comments" class="small-12 column">
+
+        <h2>
+          <%= t("debates.show.comments_title") %>
+          <span>(<%= @debate.comments_count %>)</span>
+        </h2>
+
+        <% if user_signed_in? %>
+          <%= render 'comments/form', {commentable: @debate, parent_id: nil, toggeable: false} %>
+        <% else %>
+        <br>
+
+        <div class="alert-box radius info">
+          <%= t("debates.show.login_to_comment",
+              signin: link_to(t("votes.signin"), new_user_session_path),
+              signup: link_to(t("votes.signup"), new_user_registration_path)).html_safe %>
+          </div>
+        <% end %>
+
+        <% @root_comments.each do |comment| %>
+          <%= render 'comments/comment', comment: comment  %>
+        <% end %>
+        <%= paginate @root_comments %>
+      </div>
+    </div>
+  </section>
+<% end %>
\ No newline at end of file
diff --git a/app/views/debates/show.html.erb b/app/views/debates/show.html.erb
index 3ed8b3a9d..1767266db 100644
--- a/app/views/debates/show.html.erb
+++ b/app/views/debates/show.html.erb
@@ -1,99 +1,81 @@
-<section class="debate-show">
-  <div id="<%= dom_id(@debate) %>" class="row">
-    <div class="small-12 medium-9 column">
-      <i class="icon-angle-left left"></i>&nbsp;<%= link_to t("debates.show.back_link"), debates_path, class: 'left back' %>
+<% cache [locale_and_user_status, @debate, Flag.flagged?(current_user, @debate)] do %>
+  <section class="debate-show">
+    <div id="<%= dom_id(@debate) %>" class="row">
+      <div class="small-12 medium-9 column">
+        <i class="icon-angle-left left"></i>&nbsp;
+        <%= link_to t("debates.show.back_link"), debates_path, class: 'left back' %>
 
-      <% if current_user && @debate.editable_by?(current_user) %>
-        <%= link_to edit_debate_path(@debate), :class => 'edit-debate button success tiny radius right' do %>
-          <i class="icon-edit"></i>
-          <%= t("debates.show.edit_debate_link") %>
-        <% end %>
-      <% end %>
-
-      <h1><%= @debate.title %></h1>
-
-      <div class="debate-info">
-        <%= avatar_image(@debate.author, seed: @debate.author_id, size: 32, class: 'author-photo') %>
-        <% if @debate.author.hidden? %>
-          <i class="icon-deleted author-deleted"></i>
-          <span class="author">
-              <%= t("debates.show.author_deleted") %>
-          </span>
-        <% else %>
-          <span class="author">
-              <%= @debate.author.name %>
-          </span>
-          <% if @debate.author.official? %>
-            &nbsp;&bullet;&nbsp;
-            <span class="label round level-<%= @debate.author.official_level %>">
-              <%= @debate.author.official_position %>
-            </span>
+        <% if current_user && @debate.editable_by?(current_user) %>
+          <%= link_to edit_debate_path(@debate), class: 'edit-debate button success tiny radius right' do %>
+            <i class="icon-edit"></i>
+            <%= t("debates.show.edit_debate_link") %>
           <% end %>
         <% end %>
-        <% if @debate.author.verified_organization? %>
-          &nbsp;&bullet;&nbsp;
-          <span class="label round is-association">
-            <%= t("shared.collective") %>
+
+        <h1><%= @debate.title %></h1>
+
+        <div class="debate-info">
+          <%= avatar_image(@debate.author, seed: @debate.author_id, size: 32, class: 'author-photo') %>
+
+          <% if @debate.author.hidden? %>
+            <i class="icon-deleted author-deleted"></i>
+            <span class="author">
+                <%= t("debates.show.author_deleted") %>
+            </span>
+          <% else %>
+            <span class="author">
+                <%= @debate.author.name %>
+            </span>
+            <% if @debate.author.official? %>
+              &nbsp;&bullet;&nbsp;
+              <span class="label round level-<%= @debate.author.official_level %>">
+                <%= @debate.author.official_position %>
+              </span>
+            <% end %>
+          <% end %>
+
+          <% if @debate.author.verified_organization? %>
+            &nbsp;&bullet;&nbsp;
+            <span class="label round is-association">
+              <%= t("shared.collective") %>
+            </span>
+          <% end %>
+
+          <span class="bullet">&nbsp;&bullet;&nbsp;</span>
+          <%= l @debate.created_at.to_date %>
+          <span class="bullet">&nbsp;&bullet;&nbsp;</span>
+          <i class="icon-comments"></i>&nbsp;
+          <%= link_to t("debates.show.comments", count: @debate.comments_count), "#comments" %>
+          <span class="bullet">&nbsp;&bullet;&nbsp;</span>
+          <span class="js-flag-actions">
+            <%= render 'debates/flag_actions', debate: @debate %>
           </span>
+        </div>
+
+        <%= @debate.description %>
+
+        <%= render 'shared/tags', debate: @debate %>
+
+        <% if moderator? %>
+          <div class='js-moderator-debate-actions'>
+            <%= render 'actions', debate: @debate %>
+          </div>
         <% end %>
-        <span class="bullet">&nbsp;&bullet;&nbsp;</span>
-        <%= l @debate.created_at.to_date %>
-        <span class="bullet">&nbsp;&bullet;&nbsp;</span>
-        <i class="icon-comments"></i>&nbsp;
-        <%= link_to t("debates.show.comments", count: @debate.comments_count), "#comments" %>
-        <span class="bullet">&nbsp;&bullet;&nbsp;</span>
-        <span class="js-flag-actions">
-          <%= render 'debates/flag_actions', debate: @debate %>
-        </span>
       </div>
 
-      <%= @debate.description %>
-
-      <%= render 'shared/tags', debate: @debate %>
-
-      <% if moderator? %>
-        <div class='js-moderator-debate-actions'>
-          <%= render 'actions', debate: @debate %>
+      <aside class="small-12 medium-3 column">
+        <div class="sidebar-divider"></div>
+        <h3><%= t("votes.supports") %></h3>
+        <div class="text-center">
+          <div id="<%= dom_id(@debate) %>_votes">
+           <%= render 'debates/votes', debate: @debate %>
+          </div>
         </div>
-      <% end %>
+        <div class="sidebar-divider"></div>
+        <h3><%= t("debates.show.share") %></h3>
+        <%= social_share_button_tag(@debate.title) %>
+      </aside>
     </div>
-
-    <aside class="small-12 medium-3 column">
-      <div class="sidebar-divider"></div>
-      <h3><%= t("votes.supports") %></h3>
-      <div class="text-center">
-        <div id="<%= dom_id(@debate) %>_votes">
-         <%= render 'debates/votes', debate: @debate %>
-        </div>
-      </div>
-      <div class="sidebar-divider"></div>
-      <h3><%= t("debates.show.share") %></h3>
-      <%= social_share_button_tag(@debate.title) %>
-    </aside>
-  </div>
-</section>
-
-<section class="row-full comments">
-  <div class="row">
-    <div id="comments" class="small-12 column">
-
-      <h2>
-        <%= t("debates.show.comments_title") %>
-        <span>(<%= @debate.comments_count %>)</span>
-      </h2>
-      <% if user_signed_in? %>
-          <%= render 'comments/form', {commentable: @debate, parent_id: nil, toggeable: false} %>
-      <% else %>
-        <br>
-        <div class="alert-box radius info">
-          <%= t("debates.show.login_to_comment",
-            signin: link_to(t("votes.signin"), new_user_session_path),
-            signup: link_to(t("votes.signup"), new_user_registration_path)).html_safe %>
-        </div>
-      <% end %>
-
-      <%= render @root_comments %>
-      <%= paginate @root_comments %>
-    </div>
-  </div>
-</section>
+  </section>
+<% end %>
+<%= render "comments" %>
\ No newline at end of file
diff --git a/spec/models/comment_spec.rb b/spec/models/comment_spec.rb
index 490a5cfd1..8798f4935 100644
--- a/spec/models/comment_spec.rb
+++ b/spec/models/comment_spec.rb
@@ -36,4 +36,34 @@ describe Comment do
       expect(comment).to be_as_moderator
     end
   end
+
+  describe "cache" do
+    let(:comment) { create(:comment) }
+
+    it "should expire cache when it has a new vote" do
+      expect { create(:vote, votable: comment) }
+      .to change { comment.updated_at }
+    end
+
+    it "should expire cache when hidden" do
+      expect { comment.hide }
+      .to change { comment.updated_at }
+    end
+
+    it "should expire cache when the author is hidden" do
+      expect { comment.user.hide }
+      .to change { comment.reload.updated_at }
+    end
+
+    it "should expire cache when the author changes" do
+      expect { comment.user.update(username: "Isabel") }
+      .to change { comment.reload.updated_at }
+    end
+
+    it "should expire cache when the author's organization get verified" do
+      create(:organization, user: comment.user)
+      expect { comment.user.organization.verify }
+      .to change { comment.reload.updated_at}
+    end
+  end
 end
diff --git a/spec/models/debate_spec.rb b/spec/models/debate_spec.rb
index 25e878d18..951837956 100644
--- a/spec/models/debate_spec.rb
+++ b/spec/models/debate_spec.rb
@@ -268,4 +268,34 @@ describe Debate do
     end
   end
 
+  describe "cache" do
+    let(:debate) { create(:debate) }
+
+    it "should expire cache when it has a new comment" do
+      expect { create(:comment, commentable: debate) }
+      .to change { debate.updated_at }
+    end
+
+    it "should expire cache when it has a new vote" do
+      expect { create(:vote, votable: debate) }
+      .to change { debate.updated_at }
+    end
+
+    it "should expire cache when it has a new tag" do
+      expect { debate.update(tag_list: "new tag") }
+      .to change { debate.updated_at }
+    end
+
+    it "should expire cache when its author changes" do
+      expect { debate.author.update(username: "Eva") }
+      .to change { debate.reload.updated_at }
+    end
+
+    it "should expire cache when the author's organization get verified" do
+      create(:organization, user: debate.author)
+      expect { debate.author.organization.verify }
+      .to change { debate.reload.updated_at}
+    end
+  end
+
 end
\ No newline at end of file
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 282d8d615..f9c24ec4d 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -299,4 +299,25 @@ describe User do
     end
   end
 
+  describe "cache" do
+    let(:user) { create(:user) }
+
+    it "should expire cache with becoming a moderator" do
+      expect { create(:moderator, user: user) }
+      .to change { user.updated_at}
+    end
+
+    it "should expire cache with becoming an admin" do
+      expect { create(:administrator, user: user) }
+      .to change { user.updated_at}
+    end
+
+    it "should expire cache with becoming a veridied organization" do
+      create(:organization, user: user)
+      expect { user.organization.verify }
+      .to change { user.reload.updated_at}
+    end
+
+  end
+
 end