I bought a used Trek bicycle in 2007 and I love it to death. But because it spent its life as a rental bike, used every day forever in their rentals, it seems to need extensive tune ups every year. I want so much to be able to ride again but I have to move to a place with an elevator to get it up and down stairs.

ETA I spent around. $200 to make it mine and i have never once regretted the expenditure.