How many times has the auto save feature in WordPress saved your butt? By default, WordPress auto saves posts every 60 seconds. Paul Maloney of WPZine.com has a snippet of code that you can add to your WPConfig file to decrease that time to increase peace of mind. If you don’t want to use the auto save feature, think about increasing the time to a week instead of disabling it completely.
While reading about this tip by Paul, I started to wonder if Post Revisions were tied to auto saves because if they were, decreasing the auto save time would substantially increase the number of post revisions which in turn, would substantially increase the size of the database over time. After performing some simple tests, I discovered that auto saves are NOT tied to Post Revisions. Unlike Post Revisions, there is only one auto save that is continuously over written. Also, Post Revisions are only created after the user saves the post either as a draft or an edit to an existing post. Just some food for thought.