Your steering system and suspension system are two different systems that work in tandem to keep your car under control.
The suspension system supports the weight of your vehicle and provides for a smooth ride. The steering system provides directional control of your car.
Normal driving and road conditions create wear and tear on your suspension and steering systems. All of the components that make up those systems such as struts, shocks, control-arm bushings, ball joints, coil springs and steering linkage will wear and weaken over time. This wear creates instability in road handling, excessive tire wear and ride comfort suffers.