Question: When do you up the revision number on a document?

I've been kicking around a few ideas in my head recently as I put together a post on document revision numbering. As my thoughts have percolated over the last week or so, I realized that I'd like to put the call out for thoughts to the readers of this blog prior to posting my own thoughts.

So here's your chance... what do you, readers of BetterProjects.net, think about document revision numbering? Do you do it? When do you increment it? Do you use major/minor numbering? Do you have any specific methodology is it really whenever you feel like it? What is your starting number?

Post your thoughts in the comments and I'll include them, with proper attribution, in my post!