http://www.audi.co.uk/owners-area/maintaining-your-audi/regular-maintenance.htmlTaken from the Audi Website....
The cambelt is one of the hardest working components in an engine. Made from a rubber based compound that deteriorates with time, it should be replaced in good time to avoid serious engine damage.
Cambelt wear is influenced by a number of factors including time, mileage and various sources of contamination therefore it’s essential that it’s replaced at recommended intervals.
We recommend that your cambelt is replaced every 5 years or 75,000 miles, whichever comes first*, to ensure optimum safety and performance.Cambelt replacement is a complex job but by entrusting your car to us you can be confident that the work is being done by experienced Audi Trained Technicians. And if your vehicle is over three years old, visit our Affordable Servicing section for more information about our exclusive fixed price maintenance offers.
*Not applicable to A2 or V8 RS6 models. Details refer to 2004 model year onwards.