I always pre-wash flannel. I have had some wildly varied shrinkage in fabrics from both LQS and JA's. I mean as much as 4" of shrinkage (though normally 1-2") -- sometimes width, sometimes length, sometimes both. If I was some flannel and it really pills, well it makes good dust cloths. I don't care for some of the batik flannels I have bought at the LQS -- they were stiff when I bought them and I could not soften them with multiple washings (I can't use fabric softener because of the odor).