Seth Yoder

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

Password Protection Expiration

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

ninjatech

This plugin allows you to automatically set an expiration date for your posts, ensuring they are managed efficiently over time.
When a post reaches its expiration date, it is automatically moved to draft, making it no longer visible on the front end but still available for editing or future publication.
This feature is ideal for content that is time-sensitive, such as promotions, announcements, or event-related posts, helping you maintain a clean and relevant website without needing to manually manage outdated content.
You can configure the expiration period to suit your needs, streamlining post lifecycle management.
<h3>Features</h3>
<ul>
<li>
Automatic Post Expiration: Set an expiration date for posts, after which they are automatically moved to draft status.
</li>
<li>
Customizable Expiration Date: Choose a specific date for posts to expire.
</li>
<li>
Expiration Status Indicator: Clearly see which posts have expiration dates and when they are set to expire.
</li>
<li>
Post Type Compatibility: Supports various post types, including blog posts, custom posts, and more.
</li>
<li>
User-Friendly Interface: Simple and intuitive settings within the WordPress admin panel for easy configuration.
</li>
</ul>
<h3>How it works</h3>
After creating or editing a post, you can set a specific expiration date or by edit posts. This is typically done via a simple calendar picker.
The plugin automatically monitors all posts with expiration dates, checking the current date against the set expiration.
When a post reaches its expiration date, the plugin automatically moves it to draft status. This makes the post invisible to users on the front end but still accessible for you in the backend for review, edits, or republishing.
The plugin works with most post types, including custom post types.
We’d love to hear your feedback or suggestions for additional features!
<h3>License</h3>
This plugin is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

Auto Post Expire

Sets an expiration date for posts, auto moving them to draft after the set period.

Password Protection Expiration vs Auto Post Expire