When I did a BOM last year, the kit I got each month was in small pieces and I asked about prewashing and the lady said with todays. Quality fabrics there is not much shrinkage. She also said that she's neveR had a problem. I wonder if it depends on dye lot, brand and the fact that some colors tend to bleed more just because ! I for one am usually to impatient to get started on my quilt to putz around and test every piece of fabric that comes in this house. There's a good chance that this decision could bite my in the butt someday!LOL