Seth Yoder

<p>When you password-protect a post in WordPress, a cookie is set to expire in 10<br />
days which prevents the user from having to enter the password during that<br />
10-day period. This plugin allows you to easily change the lifetime of that<br />
cookie.</p>


Password Protection Expiration

Allows you to easily change the lifetime of the WordPress cookie which allows automatic login to password-protected posts.

X-NicON

<p>A simple plugin that allows to set the date for the posts, after which will be performed one of 3 actions: “Add prefix to title”, “Move to drafts”, “Move to trash”.</p>
<h4>Features:</h4>
<ul>
<li>Set post expire date and time</li>
<li>Support custom post type (post and pages by default)</li>
<li>Action for expired posts: move to drafts, move to trash or add custom prefix for title</li>
<li>Adds class “post-expired” to post that expired on the site and in admin interface (for custom styles in theme)</li>
</ul>
<h4>Use in theme:</h4>
<pre><code>XNPostExpires::isExpired($post_id)

XNPostExpires::dateExpiration($post_id, $date_format)
</code></pre>


WP Post Expires

I haven't tried to debug what's wrong, but as soon as I installed the plugin I was unable to see the editor icons nor actually click on the "edit" to change the publishing date or the expiration date. This is a fantastic plugin idea, hope to see it fully functional.

Broke Admin

Plugin adds post expires time after which will be performed actions: add prefix to title, move to drafts or trash.

Password Protection Expiration vs WP Post Expires