I would say to treat the fabric the way it will be treated once it's sewn.
If you're going to wash your quilt in cold water then pre-wash the fabric in cold water. If you will wash in hot then pre-wash in hot... etc, etc, etc.
Also, read directions. I didn't and it was pure luck that I didn't ruin one of my quilts. I'd used a wool batt and the quilt was gorgeous. I threw it into the washer and dryer. Damp dried it and then let it finish air drying. THEN I read the directions... Luck was with me that day, let me tell you. I often forget to read the end of the bolt of fabric for this important information, or the packaging. Getting better though!