We rarely buy new cars, but we buy new tires all the time.
According to the United States Department of Transportation, the average car on American roads today is more than 12 years old. The average American drives about 13,500 miles a year, and most new tires are good for between 40,000 and 70,000 miles.
That means that most cars go through up to five sets of tires in their lifespan, even if their drivers somehow manage never to pop a tire in a nasty pothole. Some of us routinely go through tires faster than that, thanks to bad luck