For commutes, I'd say don't bother. If you're planning on doing a lot of longer rides with lots of climbing, having those extra teeth will save you a little bit of energy on each climb, which can add up. But for day-to-day riding, where the rides and climbs are shorter, I'd say the extra gearing is a crutch you may want to avoid relying on...improve the engine and you won't need those extra gears.