When do I need to replace worn shocks or struts?

There are four main reasons that determine when to replace them: 1) To upgrade performance; 2) to restore the vehicle’s designed performance (usually after 50,000 miles); 3) when the vehicle has excessive ride control conditions (i.e. nose dive, body roll, etc.); or 4) when the vehicle has a failed unit (i.e. dripping hydraulic fluid, tire cupping, excessive bounce, etc.).