If you make a pair of jeans and want to stitch the belt carriers on, you will have:
* two layers plus interfacing for the waistband
* four layers of the belt carrier where the raw edges are turned in before each side of the carrier is top/edge stitched
* another four layers of the belt carrier where you turn the end over before attaching it to the top edge of the waist band.
That makes ten layers and my old Singer 522 struggled with that much fabric. If Bernie can handle ten layers without complaining, I call that a win