When I was growing up it was a flannel sheet, a blanket, and a comforter on top. When we visited my grandmother she had quilts that were the wool army blankets used as batting. Living here in So. Cal. it's a sheet and one quilt. It's very rare I need more than that.
I did one quilt with a double layer of batting and it was not easy to put together - I ended up having to tie it.