The LA's in my area use sheets all the time and never worry about it. I quilt on my DM a Janome 8500 using sheets as backing all the time too. I've never had a sheet yet that gave me any problems when I was quilting it. I did have one quilt with a sheet backing that pilled after a lot of wear and washing but it probably had a higher poly content than I usually use. Wal-mart often has single sheets on sale for less than $15 but you do have to watch that they are not the coarse loosely woven type. I buy sheets often seconds at Len's Mills, Giant Tiger, Winners and Sears sometimes which are usually less than $10. If I hit a really good clearance, I stock up. The last time I found great sheets at $5 and my poor son who was with me commented "Hey mom, how many mis-matched sheets can one family use anyway?" I had just bought 30 for the backs of our Community Quilts.