 On the steer axle, change your shocks at least as often as you change your tires. On the drive axle, replace shocks halfway through the tire's life and when the tires are changed too. Finally, employ good driving habits. You have full control here. More conservative driving over rough surfaces helps reduce wear. Speeding, hard braking, curving, and tight turns cause tires to wear fast. On the other hand, steady acceleration, braking, and steering can extend the life, saving a bundle.