I don't wait at all. Never have, and never had a problem because of it. Only guitar I ever had that checked like hell was a guitar that has never once left Southern California, and that sat in a shop for over 5 years before I bought it. Checked like crazy over a period of a few months in my home. No logic in that, so I think it must be something about the material or application process used on the color coats of that particular guitar. It's the color coats that have checked, not the clear.