I used to make layers for every little thing
One for the rough sketch, another for the cleaner sketch, another one for the cleanest, before I even move on to inking and coloring (hoo boy, one for every shade and highlight).
Nowadays I try to tone down my fear of screwing up and just work with one or two layers. I agree it's been improving sketches to a considerable degree, so my art's been turning out a little messier but I ended up liking the new look anyway. 