Shock absorbers and struts wear out gradually, and handling and ride quality deterioration may not be detected by the driver. The average life span of an original equipment strut or shock is about 75,000 miles depending on your threshold of wear versus failure. Significant loss of function will begin by 60,000 miles but I’ve seen many vehicles with well over 100,000 miles with original struts and shocks completely dead still in service and their owners unaware of any problem.
Some symptoms, noticeable from the drivers seat, that a shock or strut may need to be replaced include longer stopping distances, nosedives when braking, an unsteady ride, and a vehicle that leans around turns and continues to bounce after hitting a bump.
The most common physical signs of worn struts and shocks include irregular tire wear and oil leaking from the struts and shocks. Worn struts and shocks lead to increased wear on tires, brakes, steering and suspension parts. Replacing worn struts and shocks now can help avoid more expensive repairs later.
