I think maintenance intervals are based on miles or age whichever comes first and not just miles.
Now, that being said, if it's a part that only wears with use and not time, then its probably fine, right !?, but the recommendation from Toyota is 72 months.
In my case I changed the timing belt at 85k miles when I bought it, and 13 years old.... There have been pictures on MUD here of timing belts that looked just fine after many more miles. I think we have also determined that the non VVTi engines in the 100 series are NON-interference, so breaking a timing belt will not damage anything....we think.
The 2UZ-FE (100 Series engine) is extremely easy on timing belts. I changed mine at 70,000 miles (dealer) and then at 170 (200K on vehicle, oversized tires). I was panicking, 130,000 miles on a timing belt, it MUST be about to snap. The thing looked brand new! I would remove the timing belt cover (one on each side, top of the motor, big black covers).
However if that is the original timing belt, and the vehicle is from the desert, or very hot and dry climate it may be time.
I purchased mine last April with 70,000 miles and went ahead and did it along with the rest of the 90K Service. Mostly did it all to have a baseline and given the alternative if a T-Belt breaks, money well spent.