I don't do much maintenance on my bikes other than putting air in the tires and lubing the chain. My Cervelo requires the least maintenance, despite the 10-speed cassette and copious amounts of carbon and alloys. In terms of saddle time, I spend the most on it in any given year. My Trek requires the most maintenance, but it gets rode hard and put away wet all winter. It also lives outside the back door and gets exposed to +35C days, -35C nights, hail, snow, rain, dust, bird poop and cat scratching.