I only pre-wash for two reasons 1) If I use flannel for my back. It shrinks more than the regular cottons so I will prewash it. 2) If I am making something that will be heavily quilted like a wall hanging. I love the wrinkily look quilts get if they aren't pre-washed, but if you are doing lots of FMQ you don't want that look. Otherwise I never pre-wash, waste of time that I could use on getting the quilt made. And I am too lazy to do boring things. Laundry is boring. P.S. I love color catchers.