I have a MY09 S3, and in my servicing maintenance plan it's stated that in all 2.0 TFSI engines should the timing belt be changed every 115 000 miles without a time frame.
I'm not saying that it should be like this, I'm just saying what's written in the maintenance plan. And I know many people from the forum that changed their timing belts every 60000 miles or every 5 years (which ever comes first).
My car is 6,5 years old and it had 64 000 miles on the clock, and for precaution sake, and also because my timing belt started to make a noise when I would start the car, every first 5 minutes when I would start the car when the car was completely cold. I did my timing belt set (belt+water pump+tensioner etc.) + alternator belt with it's tensioner a month ago at the dealer's.
Aldo my mechanic that also works at the dealer's sprayed the belt with some special belt spray, and the noise when starting the cold car disappeared, I wasn't too sure in this solution and possible tragical outcome, so I changed it to be sure.
The dealers was surprisingly the cheapest option. In my country there is currently a dealers VW, AUDI 4+ discount for parts and labour on cars that are older then 4 years.
The complete timing belt set with labor was 220£, and the alternator belt was 20£ and it's tensioner was 40£, and I bought a 1,5L of fresh G13 antifreeze that was 8£.
P.S. the mechanic said it was important to change the alternator belt as well and it's tensioner, because it's possible that the alternator belt snaps and that it can get inside the timing belt's plastic housing, and can do a lot of damage there..