I use Auto Save and have it set to save every 60 seconds. The reason I do that is I seem to have fewer crash related problems with plug-in's, bitbridge, drivers ... etc. I've never had it cause stuttering like I've seen a few folks report, but I'm not saying I don't believe them ... I imagine it depends on buffer size and the size of your project/.cwp file.
I never save the actual project .cwp until I'm 100% certain I like the changes I've made. Having it set to 60 seconds pretty much ensures that 99% of the changes I've made are safely stored. You don't have to set it by time ... you can set it to save after so many changes. I prefer to do it by time because it just seemed to make my system more stable when it saved on a regular basis.
The reason I went to 60 second intervals is, I used to have it set for 5 minute intervals but had some crashes that corrupted my regular project file and then I had to go back and make too many changes, so I set it for 60. I seem to have much fewer problems with crashes with it enabled and I have a project open for a long period of time.
I did stop using Auto Save though in X1 because there is a bug that causes the Tool Bar to lose all it's icon's and turn gray on some systems with it enabled, unfortunately mine is one of them.