I always prewash. I once had some fabrics that shrunk under the iron. However I hate pressing & squaring up. At least the excitement about a new quilt is still in the air & I usually don't have a problem getting it done. I just hate doing it. I thought that I had a way not to have to do it. I had found a laundromat that washes & presses. I thought I could teach 'em to square up but alas it's not to be. I pulled out the fabric that I picked up on fri. yesterday & it's waaaay off. Instead of cutting right away I had to square up & repress all of it.:( This is the 4th or 5th time I've used 'em & they keep getting worse instead of better. I also have a tendency to get bored about halfway through the piecing & have to work hard at finishing up the top. I love hand quilting!!!!! I make way to many quilt tops to hand quilt 'em all so I'm learning machine quilting. I do like the binding especially the hand work.