[kathyricks]

My experience has been the Toyota water pumps last 150-250K if Toyota brand coolant and distilled water is used. The timing belt idler pulleys are good for 150-250K too (at least for highway type drivers).

So I figure the best overall strategy is to do the timing belt alone at 90K and then
the timing belt again at around 160K and then do the water pump and idler pulley at that time (plus any oil seals that may be starting to leak)

The engines the call for a 90K timing belt replacement interval have a heavier duty type timing belt compared to the engines that have a 60K interval.