I think the prevailing thought is after 300-500 miles.
They are replaced when they go bad.
One week
What you meant to ask is how often should the timing belt be replaced! And the answer is every 90,000 miles for b2000 model.Ok
The Honeywell filter should be replaced every 8- 12 months or as needed.
When they wear out.
about every 2 years
Although there is no set on how often your brakes should be replaced, I would just pay attention to your car. When you notice something wrong, I would call your auto body shop.
If the oxygen sensors for the 1991 Chevy 4.3 is running rich when it is warmed up it is best to have the sensors replaced. Once the sensors are replaced this should resolve the issue.
Fridge filters should typically be replaced every six months to ensure clean and safe drinking water.
all the time
Eyeglasses should be replaced typically every two years. Eyeglasses can break or if expiration is past then a new examination should be taken to get a new pair.
Whenever they get REALLY yucky, or ripped apart.