I prewash all my yardage, but I don't buy precuts. Well, I did buy one jelly roll for a jelly roll race quilt (which I haven't made yet) and I don't expect to wash it, but that's the exception. Almost every week someone on the board complains about having problems that could have been avoided by prewashing. Other people say that they've never prewashed and never had any problems - yet. I prefer to avoid the bleeding and shrinkage, and I prefer working with clean fabric without the chemicals that are left by the manufacturing process. To each his own.