Depends on which machine I'm using and what I'm doing. The Pfaff 2140/2170 doesn't have the best bobbin winder so I'll use the Sidewinder. The 2144/2170 is a bit better at winding. However, If I have the upright spool accessory on, I'll use the Sidewinder rather than wind through the foot. Using a twin needle will also make me use the Sidewinder.