<human>:  How do I know when it is time to replace my car's tires?
<bot>: When your car's tires start to show signs of wear, it is generally a good sign that it is time to replace them. You may notice that the tread depth is decreasing, the tread blocks are becoming worn or damaged, or there are other signs of damage to the tires. Additionally, your car's manual may specify an approximate amount of time that the tires should last, and when they have reached that time you should replace them.