I think if you commute in proper winter conditions you need studs. Ice is a bigger problem than snow but you`ll get both and you do not want broken bones. Try to make it so the studs just barely touch the ground when riding straight forwards. If they are too far down on the side (can happen on really fat knobbyes) it is almost as if you do not have them at all. We had seriousely wet ice here last week so ypo could hardly stand upright on two feet. Riding was also a challenge for a few days. Now it is melting.