If you're only riding indoors on wood, than you can get away with riding only race wheels. But a lot of people save the fast wheels for big events as it gives you a bit of a psychological boost– if you do all your training on heavier spoked wheels with more durable tires, you KNOW you will be faster when you put the race wheels on. I still bring my training wheels to wood tracks, and put the race wheels on when it's time to race.