This is going to sound like a silly question but since I don't know whether its someething I should listen to or not..Ok, well, when I first started quilting, I took a class and she taught log cabins (still love them by the way), sorry I digress. The two things this instructor said we had to do was always use the same sewing machine for each top and we were to use bobbin thread. Was this just her quirk or is there a logical reason for this?