TIEro

This plugin is now available as part of <a href="https://wordpress.org/plugins/tietools-automatic-maintenance-kit/" title="TIEtools" rel="ugc">TIEtools</a>, which also includes post expiry and server log file removal.
A simple duplicate post deletion plugin. Spots posts with the same title and removes all but one of each.
<ul>
<li>Checks in published, draft, pending and private posts on demand</li>
<li>Includes or excludes user-defined list of categories</li>
<li>Moves all duplicate posts to the Trash (leaving the oldest or newest original copy)</li>
<li>Permanent post deletion is handled by WP’s built-in Trash removal</li>
<li>Power button to switch everything on and off without messing with the plugins page</li>
</ul>

TIEdupedeleter Simple Duplicate Post Deleter

Simple duplicate post deleter. Trashes duplicate posts based on status and category. Keeps newest or oldest original copy.

This plugin is now part of the free plugin <a href="https://wordpress.org/plugins/tietools-automatic-maintenance-kit/" title="TIEtools" rel="ugc">TIEtools</a>, which also includes duplicate post control and server log file removal.
Simple post expiration plugin. Expires posts based on a variety of criteria, including category and post status options.
<ul>
<li>Expires published, draft, pending and private posts on demand.</li>
<li>Includes or excludes user-defined list of categories.</li>
<li>Moves all expired posts to the Trash.</li>
<li>Notifies post author, site admin and others of post expiry on demand.</li>
<li>Permanent post deletion is handled by WP’s built-in Trash removal.</li>
<li>Completely automated by wp-cron once options are set.</li>
</ul>
Currently, the plugin offers four cumulative expiration methods:
<ol>
<li>Expire posts based on their age (e.g. expire posts created more than 90 days ago).</li>
<li>Retain a given number of posts and expire all others (e.g. keep the latest 1,500 posts).</li>
<li>Detect the BAW Post Views Count plugin and expire posts based on a combination of post age and number of views (e.g. expire all posts over 45 days old which have fewer than 100 views).</li>
<li>Detect the WTI Like Post plugin and expire posts based on a combination of post age and total number of likes (e.g. expire all posts over 90 days old which have fewer than 10 likes).</li>
</ol>
Each expiration check is run separately and in the order listed above, so you can build quite complex expiration structures to catch a variety of criteria.
Post status choices apply to all expiration methods. The user-defined category filters can be switched on or off for each method.

TIEexpire Automated Post Expiry

Expires posts based on multiple criteria, with category and post status options. Sends notifications to users and admin on demand.

TIEdupedeleter Simple Duplicate Post Deleter vs TIEexpire Automated Post Expiry