I have used new cotton sheets for backs of very large quilt. My preference is wide quilt backing fabrics. If I am planning a very large quilt I will by 120" just to be sure I have what I want. As time has gone on with my quilting I have been getting smaller and smaller. The larger quilts are getting harder to handle for me. Now If I am making a larger quilt the 108" backing fabrics are what I order. I find them to be perfect for the money spent.