Quote Originally Posted by cmm47172 View Post
My car has 90,000 miles. The owners manual says to replace the timing belt at 100,000 miles.
If I were you I'd wait until it hits 100K. The belt is supposed to last that long.

However, at that point I'd change everything that's in that area: water pump, tensioners, etc. It's a big (and expensive) job, and I wouldn't attempt doing it myself.