[JoeFromPA]

Water pumps go from age, not mileage...it's related to the pH of the coolant mixture (and the amount of time on that coolant), heat exposure, heat cycling, and pressure mostly.

My guess is 3 years is completely conservative and safe, 5 years will almost always be safe except for extremely rare failures or defects, and 10 years is working on borrowed time.

Coolant changed every ~3 years or so should make them last towards the end of that range.

Hope that makes sense.