Rear wheels, just like the fronts, can become skewed, and even a little of this can affect tire life and vehicle tracking.

Getting tire alignment and rotation is done using an alignment machine to measure the wheel angles. 

These are calculated and compared against your vehicle’s original specs. Then the technician makes adjustments as needed.  when you replace tires is one of the best ways to get the most mileage out of them. 

Be sure to ask for an alignment, since it’s not generally part of the purchase price.