I have been to China a number of times in the recent years, and seen many taxi's, buses and private passenger cars from the inside. Many cars in China are in terrible condition, especially those used as a taxi or bus. On the other hand, some privately owned cars are in good condition. The difference is that people who have saved many years for buying their car treat it with respect and care for it.
Taxi's and buses are neglected, noone cares for them. Maintenance seems to be very rare, and mechanics work very sloppy (i've seen too many cars with the steering wheel offcenter). If you only drive these cars you get the idea the quality is very bad.
Same goes for the motorcycles, although in general most chinese treat their motorbikes and scooters very bad so after 1 year they almost fall apart. If you care for it this won't happen.
So it's basically up to you, the owner. Be nice to your car