Every 80k, so you are either good for a couple of 15k, or long over due. I would take/call the vin# into the dealer and see when/if the HG recall was done. There is a good chance the t-belt was changed at that time.

If you haven't had the truck for a couple of yrs, you should also check to see if the steering relay rod recall has also been done on the truck. From what I can tell the notice of the recall only went out to original purchasers, or those who purchased ithe vehicle through a Toyota dealer. I recieved the notice for my '90(which I bought new), but not the '91 I picked up a few yrs ago.