A timing chain is responsible for synchronizing the rotation of the crankshaft and the camshaft in an internal combustion engine. It helps to control the opening and closing of engine valves. Timing chains typically last longer than timing belts and typically do not require replacement unless they become damaged or begin to stretch excessively. However, manufacturers often recommend inspecting the timing chain at regular intervals to ensure that it is functioning correctly. Any unusual noises or vibrations should also be examined as they can indicate a problem with the timing chain.