Your car's suspension system, including its shocks and struts, is just as important as any other set of parts under the hood; the suspension cushions the car from bumps and dips in the road, avoiding unnecessary wear and damage to other parts. Without a properly maintained suspension, your vehicle may be at risk for a broken axle or broken tie rods, which are very expensive repairs. Note, too, that the brakes may not work as effectively when the suspension system is in poor repair, as it's difficult to properly stop the car while it's bouncing and dipping. Consider a few unmistakable signs that your vehicle may need a new suspension system so you know when to bring the car in for repairs.
Check the shocks and springs under the car on a regular basis and note if they seem oily. If so, this usually means the shocks are leaking fluid and will soon start to lock up. You don't want to put off getting those shocks replaced in this case, as any fluid leak can cause the shocks to become stiff and unmovable before they outright lock in place. Stiff shocks will then cause other parts under the hood to absorb impact and movement, and this can lead to broken springs and uneven braking, as mentioned above.
Uneven tyre wear
Uneven tyre wear can be caused by a number of factors, including poor alignment and balancing, and even your own driving habits. However, when shocks are in poor condition and need replacing, this can put uneven weight and pressure on one tyre so that it wears down sooner than others. If you know the tyres are properly aligned and balanced but tread on one is still wearing out unevenly, check the shocks and suspension for needed repairs.
As with tyre wear, there can be a number of reasons why you may hear grinding sounds under the hood of the car, including worn brakes and rotors or a failing transmission. Worn shocks can also cause this grinding sound, as the springs are not moving freely when you brake or the car hits a bump. You'll hear the grinding or sound of metal scraping as the shocks try to move, and as the brakes try to grip the rotor while the car is dipping. No matter the cause of this grinding sound, have it checked and consider underbody repairs, as metal should never scrape against metal under a car's hood.