If you continue to drive on your worn out shocks and struts, you are necessarily putting yourself in risk of creating a driving hazard, however, statistical and physical studies have concluded that worn shock increase the stopping distance for a car driving on a rough surface. So, if you were someone that wants to keep their car in perfect driving condition, how often do you change the struts and shocks. Different manufacturers suggest different odometer readings for changing them. However,after detailed interviewing with my network of trusted mechanics, I came to the conclusion that it is almost impossible to a certain point in the car's life that the the struts and shocks are to be replaced. Some factory shocks may show aging signs after only 30,000 or 40,000 miles. Struts usually last around 50,000 or 60,000 miles. Shocks and struts do not require replacing at specific mileage intervals like filters or spark plugs. This is simply because the damping characteristics of the parts gradually deteriorates over time. And since you are driving the car pretty much everyday, the decline in the quality of the drive is going to happen with out you noticing.