The Strut and Shock Story
Struts and shocks are used to dampen spring oscillations, or in simpler words, to get the car to stop bouncing after it hits a bump. Struts have an additional function -- they are a load bearing part of the suspension system. One way to tell whether you're dealing with a strut or a shock is to think about what would happen if you removed it. If it was a shock, the car would still look normal and the car could probably still be driven. If it was a strut, the car would be laying on the ground with the tire resting on the wheel well. Struts save the auto maker money. It is cheaper to manufacture cars with strut type suspension. Unfortunately it's more expensive for you, the consumer, to replace them when they go bad since they are harder to replace and the part costs more.
The simplest test for bad shocks or struts is to bounce one corner of the car really hard. If the that corner of the car continues to bounce after you stop then the shock or strut is bad. Shocks or struts can be "bad" in less obvious ways though. It is not necessarily black and white. Struts go bad gradually; it's not as though one day a strut is fine and the next day it's bad. At what point during a struts decline you should replace it is up to you. Early strut failure is usually most noticeable on high speed sweeping turns, like a curved freeway overpass. The car may feel like it's "wallowing", a rocking sensation that feels like you are teetering on the left front and right rear wheel or the right front and left rear wheel, depending on the direction of the turn. A basic rule of thumb is, if you don't have a problem with the way a car handles you don't need to fix it.

Shocks are very easy to replace. They are usually held place by only 2 bolts per shock. Struts are more difficult. The strut assembly must be removed from the car. The coil spring that supports the car is held under pressure in the strut assembly, so a strut spring compressor must be used to compress the spring so that the strut can be safely removed and installed. We use a Branick, pictured on the left. It makes the job much easier. On many cars the camber adjusting bolt must be removed to remove the strut. It can be marked and put back in the same position, but it's probably a better idea to do an alignment after the struts are replaced. When doing rear struts the rear seat and trim often needs to be removed to get the top mount bolts, so rear struts usually require more labor than front struts.
When replacing struts we use KYB. KYB is the largest hydraulic company in Japan. They are the OE manufacturer for most of the cars made in Japan. They have a lifetime warranty and their performance is great. We are able to offer KYB shocks and struts for much less money than the OE struts and shocks.