Change the timing belt?

I have two cars: a chevy lumina and toyota camry, both nearing 140,000 miles on them. Camry had the belt changed at around 68,000. Lumina hasn’t had it changed.

1) Should I bother to change the timing belt and if so, is it very hard to do it myself or should I pay the mechanic $300+ to do it?

2)If I change the timing belt, should I change the water pumps also?


Your Lumina has a chain and it should be good for the life of the car.
The next belt change on the Camry should mean that it gets a water pump AND a new belt tensioner setup.