While there is no hard and fast rule, most mechanics recommend changing tires if you've had them fore more than 6 years. But more important than how old they are is how worn are the treads. Check with your mechanic, but generally treads less than 1/16 of an inch thick need to be replaced. To ensure your tires wear evenly, consider rotating them once a year (at every other oil change is a good--many place will even do it for free with your oil change!).
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