The key to avoiding uneven tire wear is regularly moving each tire to a
different corner of the car. This way, each tires experiences a variety
of wear patterns over time, and wears out at the same rate as the other
tires. Your car's owner's manual should tell you how frequently tire
rotation is recommended. Schedules range from every 3,000 to 7,000
miles. As a rough estimate, rotating your tires every other time you
change your oil should keep them wearing evenly. If you're getting new
tires or getting some of your tires balanced, the rotation should be
free, and some tire retailers offer lifetime tire rotations with the
purchase of a set of tires. If you're paying for a tire rotation, it
isn't especially expensive. A price of $20 to $30 is reasonable. Of
course, rotating tires requires no technical knowledge, so you could buy
a jack and a set of jack stands and rotate them yourself. You'll
probably save money in the long run.