I don’t know about you, but I edit old posts and page all the time. Remembering when you last modified a post is not easy unless you have it noted somewhere. Last Modified Timestamp for WordPress can help. This is a simple plugin that lets you see the last modified time for each post and page.
The plugin is pretty simple to use and does not have an options page available. Once installed, it will display the last time you modified each and every post. You will be able to sort your posts by their last modified timestamp. The output of the plugin is customizable with filters.
Last Modified Timestamp simply helps you remember when you made changes to each post. This is a free plugin.