The drive side is where you are most likely to break a spoke, unfortunately. I only carry spare spokes on a tour, along with the tools needed to replace a drive side spoke. For local rides, I just bring a spoke wrench with the idea being that on a 36 spoke wheel, I could adjust things well enough to get home, especially if I released the brake so it wouldn't run on an out of true wheel. This may be less of an option with a wheel having fewer spokes; I don't know.