I've only been quilting a couple of years and did not prewash my fabric at first (advice of first teacher). However, I tend to prewash now, especially any darker fabrics. I use a Shout Color Catcher in the washing machine. You'd be shocked how much color bleeds to the Catcher. I do lop off the corners of the fabric before washing. I have a front load machine (no agitator) so I don't put the fabric in a lingerie bag or pillow case. Currently, my dryer is on the fritz, so I just hang the fabric. Good fabric doesn't wrinkle too badly, so I don't usually iron until I'm ready to use it. That way get the fold lines out along with any wrinkles.