How do you know

[PhaneSoul]

How do you know when your struts are going bad??

[SmithSR]

When you hit a bump on the highway(change from asphalt to concrete, for ex) and your car rises, falls, rises, falls, like a boat on the water, with no damping(slowing) of the spring's natural reaction to compression...to rebound, and rebound, and rebound

When you see fluid leaking from the shock piston seal and onto the body

A typical automobile shock absorber cycles 10million times every 20k miles. Tell me the OEM shocks aren't due for replacement!

With your car sitting in your driveway, jounce the suspension and watch the movement of the car. Does it bounce? Does it extend, compress, then settle?

Is the car riding on the bumpstops? Yes? Doomed