I usually by border fabric separate even if it's the same as what I'm going to use in the quilt blocks. This way I know that piece is for borders. I try not to buy more than 1/2 yard cuts of any fabric unless it's for backing. It's easier to have the smaller size to work with. I may buy two yards of one fabric but have it cut into four 1/2 yards. Fabric cost so much I don't mind asking the shop to cut it the way I want it.