I have an answer different than the others here. I buy a lot of kits. I do this for a couple reasons. First of all, it's easy and I don't have to think about getting all the fabrics of a quilt that I'm wanting to make--it's all right there. Secondly, I might not get to making that quilt for a time so when I finally do get around to doing one that I've been dying to make--all I need do is pull it off the shelf and get to it.
Oh yeah, my stash (particularly of kits) is the stuff of legends among my friends. They often tell my husband that when I die, they want to come help him "manage my sewing studio" and "help him dispose of everything!" Ha!!