i was told to change the timing belt on my 2001 tt at 90k. it broke at 83k. cost for belt and replacement of bent valves about $3300. lucky for me the head wasn't damaged. will change this one after another 70k.

 

It is a safer bet to change it at 60K or 4 years. The forum at Audiworld.com have found this to be the safest bet on preserving your valves and Audi Austrailia recommends the same. And when changing the belt, check the water pump, stock pump has plastic impeller which often is failed by that time as well. Most replacement pumps have a metal impeller. You should also replace the tensioner and the thermostat at the same time.