I change gears all the time. Usually I'll have two rear wheels with flip hubs for the possibility of four different cogs, and I'll change rings as needed. Also, there is a vast difference in the quality of chainwhips. Use this:
Rather than this:
And it'll make your life much easier. Notice how the chain is strung up on the chainwhip. It makes a huge difference. Shimano's "Track" chainwhip is the best, IMO.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter