I don’t on the seats I do. Only time I do, is when a design is sewn into the cover and needs it.

Remember also when doing certain stitches in motorcycle, atv, dirt bike, etc seats they are more vulnerable to foam saturation unless wrapped with a barrier. I’m still on the fence about wrapping foam with plastic to prevent saturation. I do a lot of boat work and see it from the factory all the time but I also see when a customer doesn’t maintain their boat and it builds algae and mold under the plastic on the foam causing a mess and rapid deterioration.