Shocks are designed not just to dampen out the road bumps and irregularities. Most think the weight of the car is keeping the wheels (tires) on the ground when the automobile is in motion but in all actuality it is the shocks and suspension. Often you might be driving down the freeway and notice that the car next to you has one of the wheels bouncing excessively, this is usually caused by a faulty or worn out shock absorber(s). Every split second the tire isn’t firmly planted on the ground, the vehicle is not is complete contact with the road. There are accidents every day that are caused by worn out or faulty shock absorbers. After an accident, the reason for the loss of control is never determined or most don’t worry about this, they just take the blame onto themselves for their lack of car handling skills when all along the suspension was far from adequate.
There are a few ways to determine the condition of the shocks. First you can drive the car paying special attention for excessive chatter and movement from the suspension. Further pinpointing can be by the feel of the steering wheel for any road feedback, steering wheel shimmy can be cause by worn out shocks. Secondly, body roll and excessive movement such as like with a boat is usually the sign of a worn out shock(s). Third, when the car is up on a service facilities hoist or lift, the mechanic can manually push up on the tire in a vertical direction to feel the shocks pretension or resistance but this is very subjective such as the first two items. The most conclusive shock test is to spot leakage from the shock absorber, this indicates a definitive diagnosis that the shock is faulty and needs replacement but do not wait for leakage to replace your shocks.
I once purchased a new car, one of the features I really liked about the car was the firm and great handling suspension. After about 5k miles, I noticed that the shocks changed drastically in a fairly quick way. From that point until about the 80k mile point, the shocks stayed the same, somewhat of a rolling chassis, too soft for my likening. At the 80k~ miles point the shocks really needed to be replaced. This is a very common wear patter for most German automobiles and most do not know that the shocks are not 100% at such a low mileage.
When shocks are worn and weak, they can cause a feathering wear pattern on the tires that is often misdiagnosed as a loose suspension component or misalignment of the suspension. Have your technician inspect your shocks carefully.