Volkswagen Repair: VW Jetta timing belt, vw jetta, recommended replacement

Question
My mechanic is telling me I should replace my timing belt just because my car has 75k miles on it. The mechanic did not mention seeing any signs of problems with it, I just went in for my regular oil change. So, they are telling me to do this basically as a preventative.  My question is, is this really neccesary.  Wouldnt't I feel/hear/signs if  something was wrong with it, my car runs very smoothly. I do not want to spend all that money if I don't need to.

Answer
Samantha,
  If you have a TDI, then 80k is the recommended replacement schedule.  All others are 105k.  However, keep in mind, should this belt break it could do severe damage to the engine.  If you are low in miles, yet long in years (10+), you should replace it anyway, because rubber deteriorates regardless of actual usage.

- Rick