I'm cheap so I generally only buy for a project. If I don't have a project in mind, I will tend towards buying a FQ pack or layer cake or something like that. If I am not buying pre-cut, I will probably only buy a yard if it's a good sale. I know I should buy more, but I just can't afford to spend the money. I can usually get a whole quilt out of a yard by adding other fabrics.
Cheers!
Rachel