I use vintage machines, most being built into a cabinet with a knee controller vs a foot pedal. I don't turn off the machine, nor unplug it. But I do fold the knee controller into the position that it cannot operate. Too easy to accidentally bump it with my knee while fiddling about, cleaning and oiling.

My hubby bought me one of those headbands with a light in the front, kind of like a miners' hat. It does the job great and leave both hands free.