As a general rule I buy 2 yards. But if it is a great sale, like a quilt shop going out of business, I buy 3-6 yards. If a fabric catches my eye but I can't envision it in a project I only buy one yard. I also only buy one yard if the fabric is trendy. I wish I would have learned that years ago - I have an entire shelf full of fabric that is outdated - either the color combinations in the fabric or the design.