I wash too. Just found the color catchers and I don't prewash fabric anymore. I was very happy I washed the quilt with the color catchers. They came out pink and I used fabric made by one of the best mfgs.
I always my quilts (except for art quilts) before giving them away and include a brief note on how to wash it if needed. I have had some colors bleed a little. Thank goodness for the color catchers. They work.