I like to use a pattern as a guide. But I rarely take a pattern to a LQS and buy the fabric for that particular quilt. I think I did that once when I decided to pick up quilting again after many years away from it. Like so many women, I just didn't have time to sew when my children were young. That quilt is still a UFO in my scrap basket. The piecing is so bad I just can't bring myself to quilt it. But I can't bear to get rid of it either. LOL. I use a pattern like a recipe. If I don't have something or if I don't like something, I change it. It's usually still good and I don't have the stress of spending time and money unnecessarily.