I'm a lifelong cyclist, always cycled, will cycle as long as I'm able. Never got around to doing all the maintenance myself though, besides fixing punctures. Never had the tools, never had the patience, never had the confidence. I only have one bike, which I use every day, so making a mess of it would put me out of business for a few days as I would have to haul it to the nearest repair shop, wait for it to get fixed etc. I've relied on bicycle repairmen to keep me mobile, and they've done a great job so far.