I never wash quilt shop fabric, even flannel
UNLESS there is red or a dark blue or black. But I will wash all the fabric for the quilt so they shrink (or dont shrink) the same when quilt is done. And remember to keep lights and darks separated.
and I run a straight stitch around the edge of the fabric to help with fraying before washing.
I like my quilts with a little dimension, not all flat and well, flat. There is nothing wrong with flat, everyone has their own taste. So the minimal shrinking that occurs is just right for me and everyone i have made a quilt for loves it too.