brendannee

Keep your site’s content fresh. This plugin adds a box to the WordPress admin dashboard that lists all pages that haven’t been updated in recently. Every time you log in you’ll be able to quickly see which pages might need review to ensure the content is still correct and everything is up to date.
You can set the threshold in days for considering a page “old”, the default is 90 days.

Old Page Reminder

This plugin adds a box to the Wordpress admin dashboard that lists all pages that haven't been updated in 90 days.

Tim van Iersel

Change the browser tab Title when the tab is not active as a reminder or to get the attention back from the user.
The variables that can be set are:
<ul>
<li>Time before the title changes</li>
<li>The title when page is inactive</li>
</ul>

Browser Tab Title Reminder

Change the browser tab Title when the tab is not active as a reminder or to get the attention back from the user.

Old Page Reminder vs Browser Tab Title Reminder