I wash mine after every use. I have three (all Judo style GI) and I like to use my KI brand. If I don't wash it after every use you can tell.
My least favorite is an unbleached GI that is my back-up as it doesn't seem to feel right on me even though it fits.
As for folding, traditional folding involves tying your belt around the folded GI right? That's how I was tought.