I'm one of the few that uses 3". When I started quilting I did the wrap binding, then the 2 1/2" binding. I saw a trunk show by M'lis Rae (can't remember the last name) and she said she did 3" bc she wanted to be sure she got a good bite on the edge. The edge, binding of a quilt is the most handled part of a quilt. It made sense to me so do a 3" binding.