Revisions is a post type and a feature in WordPress. It enables WordPress to automatically save revisions of posts, pages, or custom post types every 60 seconds during the editing process. Revisions were added in WordPress for two very important reasons and one of them is to prevent the risk of losing data. A simple browser or computer crash can erase hours of hard work.
In the old days of WordPress, the problem was that you would simply lose all the work that you didn’t save it manually. Thanks to Revisions, you don’t have to constantly save everything. WordPress does it for you, so you don’t lose any data if something goes wrong.
The other important reason for adding Revisions was to improve the editorial workflow. There are times in writing when you make mistakes or get rid of an entire idea without thinking it through. A day or two later, you want to go back to that initial idea. Well, revisions allows you to compare the different post versions. You can even restore an older version of your post if required.
Revisions autosave interval can be managed by defining WP_POST_REVISIONS in your wp-config.php file. You can choose to save revisions every 30 seconds, every 2 minutes, or anything else that you like. You can even turn it off completely.