Recently made a flannel quilt for DH. Prewashed everything. I'm sure it all shrank, since I didn't premeasure, not sure how much. I had high quality from LQS, thinner from Joannes, and assorted leftovers from a friend. After washing the thinner flannel from Joannes was noticably narrower and also thicker. It felt more stable. I liked the change. And since all have been prewashed to shrink and remove some extra dye, I think they'll play better together.