Usually the first symptom is the car doesn’t seem to steer the same as it used to

Because shock absorbers wear out over time they are often unnoticed by the owners or drivers of vehicles. It is often not until they are replaced that the level of wear is noticed, which can potentially be a serious problem.
If you notice the ride getting rough or the vehicle skipping around on bumps, or even the braking distance of your vehicle increasing, it is often a major sign the shockers are in need of attention. (Don’t delay having your suspension checked by a qualified technician)
As a general guide shockers begin to wear out at about 40,000 km with heavy usage.