Timing chains, and timing belts to a degree, have, for decades, been a repair only item. Today, however, the systems used on engines make ignoring them a potentially bank-breaking experience, especially if you own an interference engine – so called because if the timing belt/chain breaks or otherwise loses sync, the valves will contact the cylinders, causing engine damage. Even with a non-interference engine, timing belt/chain failure will leave you stranded, as the engine cannot run without it. Ideally, it should be replaced at regular intervals to prevent the added expense and inconvenience of an unplanned breakdown.
Many late model engines incorporate timing chains in conjunction with variable timing systems. These may wear out prematurely and put the check engine light on. Some manufacturers allow us to monitor this wear in scan data, which lets us recommend service before damage is done or emissions or driveability are affected. If your vehicle does have a timing chain, we have found that full synthetic oil, changed at intervals less than the manufacturer's recommendations, can help to greatly extended the service life of the components.