So far I only use the for rag quilts but do wash them once. If I had a quilt with other fabrics mixed in I'd probably do it more but with all flannels, and most coming from the same source I only wash once because I know they'll shrink. My rag quilts turn out great so its working so far. I'd definitely do it more if I was using it as backing for cotton, the cotton would get washed as well.