I am not much on using sheets as backing for any of my quilt shop fabrics; however, if I am making charity quilts with donated fabrics, I have used sheets if I do not have a coordinating fabric. I do use new sheets with a high thread count from sale rack because if I spend all that time free motion quilting little stars and circles, then I want it to last a long time. The main reason I do not care for sheets is because my fingers get so sore and cracked with the cheaper fabrics. I wear gloves when quilting but not when piecing.