My car has about 104k on it and after the last oil change (every 3k) my
mechanic told me that I needed to have the timing belt/water pump
changed. I was also told that failure to do this could destroy the
engine if the timing belt failed.
Is he right?

Also, how many miles for this maintence? Some sites seem to say after
60k -- in which case I'm driving on borrowed time here, and others say 100k.

Thanks,

Dylan