I just sold my Cranboob with 2000 + miles on it. I did all the things I outlined here- http://motorbicycling.com/f30/guide-...-care-354.html
and then rode it for two years, with no problems.
Stay away from rough patches in the road and treat it with respect and a Cranboob will last a long time.
They are really cheap(ly done) bikes.