That is a great, simple formula Lynette! I've always used a 3 yard rule (if I might use it as a border, or background - 3 yard minimum.) If it has lots of colors that I can match, I''ll buy 1 1/2 yards (1 yard cuts never seem to work out for me for some reason - I always seem to need a bit more.) Backgrounds I'll buy from 3-5 yards. Then again, I've found that I like to make patterned quilts and really don't do anything scrappy, so buying fat quarters or fat eights really doesn't work for me.