How often timing belt tensioners get changed?

Howdy,
I'm wondering how many people get the timing belt rollers and the tensioners changed during a timing belt service. We've done five engines so far with mileages from 46K to 132K and have found all the timing belts looking like new and the rollers and tensioners looking from excellent to poor. We replaced almost all of them, also replaced the seals and water pumps. How many of you had all these replaced at the same time? How many have had failures of the belt, tensioners, etc?