If they're little 'uns, pinching. The bigger they get the woodier they get and are good for snips. Don't pluck anything unless you get yellow, dying leaves right at the end of flowering. Although they'll die and fall of on their own and are inconsequential, there's no need to pluck them... right at the end of flowering. You can wind up pulling a long fiber strip below a healthy leaf if you pluck. It's like a string from celery. I'm not going to tell you what it's called because I don't know.
Also think about how much you're going to defoliate. If only a few leaves, pinch. If you're doing a full on, go with snips or a combo.