Believe it or not, all four tires don't wear at the same rate. Depending on what type of roads you drive on, how you drive, and where you drive, each tire will wear more or less than the others. To ensure that all four tires are even, you'll have to have them rotated every so often. If you don't, the whole set will need to be changed out for brand-new tires, which is way more expensive than a simple tire change.
News & Information About Tire Rotations
So, how do you rotate the tires of a vehicle?