some only sew by hand, some sew the back on by machine and then fold it over and sew the front by hand. I don't think it matters unless you will enter it into a quilt show because some of them have rules. I personally just completed binding two smaller quilts and did the whole binding on the machine. On top of that I found some premade quilt binding that I liked and used it, it's already folded with the back piece being slightly bigger than the front so that you are more likely to catch both fabrics when sewing it on both sides at the same time by machine. I used a decorative stitch so it looks really nice. Plus since the small quilts are going to kids the sewing by machine will hold up better; in my mind. Since I only worry about the police that can put you in jail I don't care what the quilting police say. Every one has an opinion on how it has to be done. I think you should do it the way you want.