I have found that as I get better an better at binding, I use more narrow binding. I now cut it so it is 2.5 folded and that make a nice snug narrow binding for me. I find that the 3" often leaves an extra wide binding that is not as "thick" as the rest of the quilt. I actually turn under an extra 1/4 in on the folded side when doing the final stitching of my binding.

If you are using a walking foot to attach it to the first side, the seam allowance may be more like 3/8, which will add a bit more fabric filling up the edge.

hugs,
Charlotte

DogHouseMom, Thanks for that link. Sometimes I just want a little bigger binding, but wasn't sure how 'deep' to sew on the front to make it work