Shocks and/or struts should be replaced every 50-100K miles. I realize that is a large variance of mileage and that is due to the type and style of suspension that you have on your vehicle. Most manufactures do not list a replacement mileage, but shocks and struts are very important to your vehicles handling and stopping ability. When they are worn it can take longer to come to a stop especially in an emergency situation. Most people don't realize that there car is even handling differently since typically they wear slowly.
Why am I saying shocks and/or struts - well not all vehicles have the same components. Cars can have a combination of struts in the front and shocks in the rear, all struts or all shocks, pickups will have all shocks or on occasion struts in the front and rear shocks, I haven't seen struts in the rear of a pickup but that doesn't mean that it can't happen.
They are just as important though as your belts, hoses, fluids and other components of your vehicle. If it's been awhile since you've had your shocks and/or struts checked out then you probably should.
Safe Adventures ~