Vehicle suspension misalignment can result in rapid, irregular tyre wear, which is bad news for your pocket and can affect the handling and safety of the vehicle.
If your suspension is misaligned by 4 mm (just 2 mm per wheel), then for every mile you travel the tyre is being forced sideways by 8.4 metres (28 feet)*.
No wonder incorrect alignment results in excessive shoulder wear!
*Calculations based on a car fitted with 15" wheels.