99.9% of the time I have my machine on "cruise control". I move the speed down to next to nothing if I'm doing something really fiddly. Or even hit the up/down button if I want to be really cautious. I would have to look pretty hard to find my food pedal right now. So it really doesn't matter what I have on my feet! But having said that, when I come in the house I take off my outside shoes, and put on my indoor shoes. I find I'm more comfortable, and actually safer on the stairs, when I have shoes on my feet. So, my final answer is...... "shoes on"