Have you been experiencing more bounce in your ride than before? Are you really feeling all the imperfections in the road that you could swear you've never felt? If so, then take a look at your struts and shock absorbers. You might see that some of the hydraulic fluid has leaked from them and collected a lot of dust and dirt. This means that the valving inside the shock is not performing as well as it should, and the strut is no longer damping the force of suspension impact. You can test this by simply pushing down on your vehicle's bumper and seeing how quickly it bounces back up. A bad set of shocks will exhibit very slow rebound. While not an immediate emergency at first, this could ultimately result in a severe lack of control of your vehicle when your shock or strut would normally absorb a sudden impact and stabilize the chassis. Not to mention the strain that a faulty shock absorber or strut assembly could be putting on your springs. If your springs are the only parts that are supporting the chassis, then they are working way too hard and you need new shock absorbers and/or struts.
Organized auto racing has always been a space for innovation and a testing ground for new technology. Shock absorbers were first used on race cars at the turn of the 20th century, and due to their performance on the track they became standard equipment on virtually all production cars several decades later. A shock absorber dampens the travel of the spring by forcing a valve and piston down into the body of the shock where it compresses hydraulic fluid and gas. The heat and potential energy created by this process then forces the piston and valve back up providing smooth vertical motion (which transfers to the control arms or axle shafts) and variable response rate to impact. One major disadvantage of using shock absorbers is the lack of horizontal support. This necessitated the invention of the strut assembly; a more durable version of a shock which incorporates the coil spring into its design, and mounts between the steering arm or hub carrier and directly to the body of the car. As cars and trucks have become more complex, so have their suspensions. Air shocks and electronic struts can be found on luxury vehicles today, and provide the smoothest and most comfortable rides.
Shock absorbers were the original damping mechanism, and are still used on most light trucks' rear suspensions. Struts are standard on almost all passenger cars today, as they have eliminated the necessity for an upper control arm and save on production costs. That does not mean, however, that they can be ignored. If you need to replace your struts or shock absorbers, it can be done. However, proper precautions must be taken before and during installation.