Vehicle components (bushings, bearings, shims, etc.) will typically wear out over time and are not covered under warranty.
Vehicle components are subject to constant movement and in turn will wear components at different rates. For shock absorbers, the typical lifespan of a shock can vary depending on use, road and weather conditions. Ultimately how you drive the vehicle can affect the rate in which the shock is wearing, so if the vehicle is driven harder, it will typically have a shorter life. You should have your shocks and shock mounts inspected by a certifed technician at regular service intervals recomended by your vehicle manufacture to determine the amount of wear and tear on your shocks at that time. Worn or damaged shocks and or mounts should be replaced.
Time, mileage, and enviroment are considered part of normal wear and tear.
Please note, typical "wear and tear" such as bushings, bearings and valve shims are not covered under warranty unless attributable to a defect in design, material or workmanship.