I seldom pre-washed in my 'earlier' quilting days. However, with making the NICU quilts, prewashing is a must, and I host and participate in several swaps - prewashing is a must, and I find that I am beginning to use more reds and rusts in my blocks - scared of the dreaded 'run'...I also notice that when I do wash, the fabric weave seems to be a bit tighter and when I starch...it works just so much better...for me anyway.