I check how many blocks I need for the size I want to make. I'll make so many blocks in a day. I also will make a block out of scraps to see if I even want to fool with it. If I don't like it I'm not out much and it gets added to the scrappy sampler then I go onto another pattern. I always buy extra yardage to allow for shrinkage and because too often the instructions for yardage amount are a little off.