I used to buy enough fabric for only one project... but I'd buy a bit more than needed 'cause I was still learning and if I messed up, well I could just sew the extra fabric rather than take that dreaded seam-ripper out. As I got better I built up a tiny stash with the extra fabric I wasn't using 'cause I wasn't messing up. Then I made my first scrappy quilt from the leftovers... and boy am I hooked now. I buy remanants and fat quarters 'cause the budget is still really tight but I find that now I crave the variety.