I replaced the timing belt at 100k 10 years ago. I live in Buffalo, NY (not hot in summer) and the car is garaged all the time. I am retired. I am including some pictures of the timing belt. It looks new, no cracks, discoloration, or other. Is it possible that it could last longer under these conditions? I have 155k on it now. If I should, is it possible to just change the belt since the idler and tension device and water pump have only 55k miles on them.

 

They embrittle with time and one cannot easily see it.

I think a decade's probably enough - it's far cheaper than a new engine!

You don't necessarily need to replace the pump/tensioner @ 55K miles. It's just more cost-effective in case they do weep/wear and then it's another belt.

You might want to replace the harmonic damper if it's not been done - they don't like being pulled off the nose of the crank and sometimes the rubber ring detaches thereafter, wearing through the timing belt cover with disastrous consequences.

It's a bit awkward to get your finger down there to confirm it's still in place.