WordPress is an amazing publishing platform. Part of its greatness is how user friendly it is, with Revisions being a particular case in point. I can’t count the number of times that I’ve had to load up a previous version of a post to reclaim some literary nugget that I accidentally deleted in a fit of writer’s angst.
Unfortunately, in order to save me from myself, it has to use quite a lot of database space. Each revision means one more row in the Posts table, on top of the canonical version that you create every time you hit the Update or Draft versions. If you are like me and painfully obsessive about every single word, or you write epic 5,000 word posts, then that one post could have 20 or 30 revisions saved in addition to your working copy.
Multiply that by the number of posts on your blog, and it could quickly run up to the hundreds or thousands of rows.

