I used to sit with my great grandmother and help her thread the needles on her old singer and would sit and chat. I recall her telling me to back a quilt with a brand new sheet...make sure it was crisp and all ironed out. After she passed away and a few years after that. My mom and I took the last quilt she worked on the to ladies guild to have it backed and quilted. That question came up then also....The guild recommended not to put a sheet on it, however, would depending on what we wanted on it. I don't recall the reasoning behind it. My mom purchased a very pretty blue sheet and they back the quilt and my mom put it away tucked in the back of the closet and when I got married 15 to 18 years later she gave me the quilt for a wedding present from my great grandmother. I will occasional put it on the bed when family is coming just to show it off but don't sleep with it and actually use it. Then when company leaves I fold it back up and put it in a canvas bag and back in the closet it goes....lol.
I myself started quilting about 9 years ago and I was taught in every class NOT to back with a quilt. One teacher taught a whole class NOT to use fabrics from a local store because of the quality of the fabic and the processing used in some of the textile mills which allows the fabric to stretch out of shape once washed. One teacher said that the amount of sizing in a sheet could choke a horse....LOL. I have not found anyone today that used sheets as backing....Before I got my gammill, I used to use 2 different Longarm Quilters and neither one of them will allow you to bring in a sheet as backing. I will see if I can find out their reasons behind it!!!
I am interested in hearing everyones opinions and reasons as to why!!! Thanks