I believe it is a major fabric sin to not prewash. But I started quilting with kits and well you just can't prewash some of those small pieces. Yesterday I washed my first NON-prewashed quilt....I sat on the floor next to the washer the entire time...the buzzer went off I was sick to my stomach as I opened the door, pulled out the quilt....not a problem, it looked perfect!
Glad you asked about Batiks, I want to make a purple and yellow one but I hear horror stories about bleeding. Im mentally storing everyone tips from this thread.