Your vehicle will need new tires after every six or so years. With good care, you can have the tires for ten years or more. New vehicles come with tire pressure monitoring system that tells when you need to inflate the tires. If this light is always on, then your tires lose pressure so much, and they may have a huge leak. These vehicles also have a tire wear indicator system. The indicators start to show when the treads wear down enough.
There are other signs to check, including obvious damage. Cracks, bulges, cuts, uneven wear, items embedded in the tires, and frequent need to inflate also indicate tires need replacement. If you monitor your tires often, you will notice these signs with ease. You may also notice that the tires vibrate and make noises even after you inflate them. These challenges can lead to significant loss of gas mileage.