for what it is worth, I have been doing mine every 100,000 and have changed 3 on my '06. I know that you can't really tell if the belt is going to fail, but they have all "looked" good when I have pulled them out.
I don't doubt that the belt can last 100k, it's the other timing belt components that I doubt, primarily the small idler roller.
I guess I'm in the group that would rather error on the side of caution, and like to follow the suggested guidelines for preventative maintenance. Plus I've tried to learn from life lessons gained over the past 10 years of being around TDI's on a professional level.
Think about it for a moment though folks, it's called
preventative maintenance for a reason. Can you push the boundaries? Absolutely. But why? Why take the chance of catastrophic failure? Preventative maintenance guidelines exist so bad things don't happen to your car.
I have over 600k on my daily driver, original motor & transmission, I didn't get this far by pushing the boundaries of preventative maintenance. I can respect others opinions, but at the same time I dislike it when I have customers call me up saying that XYZ part broke, all because they read online that it could last X amount of time instead of following the preventative maintenance schedule.
I think I've said enough now, lol.
Happy driving all,
Ben