Experts recommend replacement of automotive shocks and struts at 50,000 miles. Testing has shown that original equipment gas-charged shocks and struts degrade measurably by 50,000 miles*. For many popular-selling vehicles, replacing these worn shocks and struts can improve the vehicle's handling characteristics and comfort. Unlike a tire, which rotates a specific number of times per mile, a shock absorber or strut may compress and extend several times per mile on a smooth road, or several hundred times per mile on a very rough road. There are other factors that affect the life of a shock or strut, such as, regional weather conditions, amount and type of road contaminates, driving habits, loading of the vehicle, tire / wheel modifications, and the general mechanical condition of the suspension and tires. Have your shocks and struts inspected by your local Monroe Expert Plus dealer or any ASE Certified Technician once a year, or every 12,000 miles.