Shocks should be inspected at 50,000 miles and then every 12,000 miles after that for signs of wear. Shocks are an integral part of a car's handling and braking performance and excess wear can cause a severe drop in key safety metrics like 60-0 braking distance. The simple fact is that every car is different. Some are driven only on the highway during rush hour while others are taken down dirt roads every day.
Worn out shocks can cause a car's 60-to-0-mph braking distance to grow by ten feet. The next time you come to an unexpected stop, look ten feet in front of you and imagine your car there. That's how important good performing shocks are.
Shocks can wear out and cause unsafe handling without obvious intrusive problems coming up, but here are some signs of completely worn out shocks:
Leaking hydraulic fluid
Bouncing or porpoising on rough roads
Body roll in turns
Popping or grinding from shock during movement (for more info see our FAQ on suspension noises)
The old rules don't apply: In the old days, all you needed to tell if your shocks were bad was to hop up on one corner of your bumper and hop off. If the car kept bouncing, you needed shocks. If it returned to level pretty quick, you were fine for a few more months. Nowadays if you did that, you'd rip your pretty painted bumper cover off your car and have an even bigger repair on your hands.
Just because your car doesn't porpoise down the road or lean through turns or bounce around when you push on it doesn't mean that your suspension is performing as well as it should. Modern cars are better than they ever were in the past, but modern roads are faster than they've ever been and today's drivers are a lot more willing to take chances than ever before. Your car with worn out shocks might handle and stop better than your first 79 Caprice ever could, but when you were in the land yacht, you didn't have to worry about overcrowded roads with texting teenagers missing a stop signs or distracted drivers drifting into your lane or the hundreds of other scary moments we see on a daily basis. In all those scary situations when seconds matter, your shocks matter.
When You Should Replace Your Shocks:
At 50,000 miles, you should be prepared to change your shocks. An inspection by a qualified mechanic will tell you whether a shock replacement is necessary.