If a quilt is going to have red in it I will wash the red fabrics first. If it is flannel I will was it for shrinkage first. Most others I do not pre-wash unless requested. I will do a test block and I save those test block for a quilt in the future that will be made of all those blocks trimmed up. I have only had one failure on a quilt where the fabrics fail totally. That was a recently made baby quilt. That made be a bit gun shy for a bit but now I am back on a roll.