It depends on whether you're going to quilt it yourself or send it out to someone else. I know that long arm quilters usually have a certain number of inches that they want around all sides. I quilt all of my stuff myself and on smaller items, I usually only go 1-2 inches around the sides, but I also make sure to baste well, so the fabric doesn't move on me. There are several factors to consider when looking at the backing.