Timing belt has time as well, Manufacture recommend every 6 years regardless of miles , just to let you know . I know some people drive over that , but however there is a many cases that T/ Belt slip after 6-7 years .
I've never seen a single one fail from age. I just did a 1998 ALH a couple years ago with 17k miles on it. Belt still looked perfect. I've done a half dozen 2010s over the last year that all looked perfect, too. One had 180k miles on it.