When should t?he timing belt be changed? What is the average replacement cost?

it should be replaced at around 60000mi

I am trying to find out, too. I have a 1995 Toyota Corolla with 250,540 miles, and I know the original owners say they had the belt changed at around 100,000 miles. A mechanic told me if the belt breaks it will not harm the engine. Another report was that on makes prior to 1997 Toyota did not state a specific mileage for timing belt change and that unless the car was used in extreme conditions it was not necessary to do so. I know timing belts should be changed based upon mileage not age of car. Cost? Depends on your area and to whom you take the car. I have heard anywhere from $300-450. If you find out anything more definitive, I would be eager to hear.