When should you replace the timing belt on a 2001 Toyota Celica GT?

The vvtl and vvtli motors are chain driven. Chains are superior to belts in many ways including wear. I've heard of a lot of 7th gen celicas hitting the 200k mark with only changing the air filter and oil. I would say do it at 150k just to be on the safe side, Do the water pump while your in there. That way you know your good until at least 300k. At least on that portion of your motor.