I buy yardage. If I see fabric I really like I buy a couple yards at least. Whenever I buy fabric for a specific project, I usually but at least 1/2 yd more as a safety net in case I make a cutting mistake and to have some leftover for a scrappy quilt. I do buy a few fat quarters sometimes if I'm making a scrappy quilt and need a few more colors/prints. If there's a really good sale, like 50% or more off, I'll look for fabrics that would make good quilt backs and buy 5-10yds. Good luck building your stash!