When should you change your timing belt on a 2003 Toyota Corolla?

There is no Timing belt in corolla 2003 to 2008 model, Toyota start the timing chain for all these series that's what the Toyota dealer said.Your Toyota timing belt/timing chain plays an important role in the running of your vehicle. The Toyota timing belt/timing chain is typically tucked away behind the front cover of your engine, but just because it is out of sight does not mean it should be out of mind. Indeed, far from it, your Toyota timing belt/timing chain must be in working order for your vehicle to be operational. The Toyota timing belt/timing chain winds around the camshaft and crankshaft, and is assisted by the idler pulley/tensioner. It is responsible for seeing to it that the valves operate at the right time sequences to permit the correct amount of air and fuel into the engine, as well as allowing exhaust to escape. Clearly, if a malfunctioning Toyota timing belt/timing chain is not allowing air and fuel into the engine, your vehicle is not going to get far. The Toyota timing belt/timing chain is a part that should be changed according to the recommended maintenance schedule, whether or not it is showing any wear. That is because this is a part that can, and often does, fail without warning. While estimates may vary between individual automotive technicians, the general recommendation is to replace the Toyota timing belt/timing chain at about the 60,000-mile point. However, if your driving circumstances tend to be a bit more demanding than those of the average driver, you may want to consider replacing your Toyota timing belt/timing chain a bit sooner.