If it is dirty, or every 2 years.
90,000 ks
It has a chain
It should be replaced when it begins making a noticeable noise.
I wouldn't recommend it if it hasn't leaked.
Yes it should be!
It goes by mileage ....100,000 miles is recommended
At around 90000km timing belt should be replaced!
Listed in your owner's manual.
Timing belts for most vehicles are supposed to be replaced at 60k. Some vehicles at 90k.
120,000 miles , according to the Gates website
Never. This is not an item you replace at a scheduled time or mileage. It should last the life of the engine.
If the timing belt has not been replaced during prior visits the 105k interval is when it should be replaced regardless of inspection. It should be checked at 60k and 80k for the 1.8T, and if there are signs of wear at that time replaced.