By Seth A. Yoder Password Protection Expiration Plugin
Allows you to easily change the lifetime of the WordPress cookie which allows automatic login to password-protected posts.
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.
Installation
Unzip into wp-content/plugins, then activate via the admin panel. Settings are
in Settings -> Password-Protection Expiration.
Changelog
0.2 – Added settings page; expiration time now based on a WordPress option.
0.1 – Defaults to 2 hours