When I was a kid, we spent lots of time with my DGM, and all of her quilts were backed with flannel. Until I started quilting myself, I thought ALL quilts were made that way. For a while, I went to the cotton backed quilts, but nostalgia won out, and I started putting flannel on all the quilts I do for family members. If it is a wall hanging, then I use whatever is handy, but for quilts that I want to be soft and snuggly, it's flannel.