The function of the shock absorber is to keep your tires on the ground thereby providing better traction and steering control. There are a couple ways to determine if your shocks are bad or worn. The first is to look at your tires. If you see scalloping on the edges, the tires is bouncing off the road too much and the asphalt is wearing the rubber of the tires. You may also notice "tire chatter" especially when driving on wash board roads or around corners. If this occurs, a simple inspection of your shocks may show the fluid is leaking from one or more of them and it is time to change the shocks. Some may say that your shocks are fine if you press down on a corner of your vehicle and it does not bounce when you let up. This could be true for a smaller, lighter car, but the size and weight of the Range Rover make this a pretty useless test. One cannot compress the springs enough to force a response from the suspension.
Internal valves within shock can also fail allowing the fluid to travel more freely between the upper and lower cavities than it should. This is a simple function of wear and is difficult to measure. Range Rover shocks have an extraordinary travel of almost 10" as opposed to the standard 4 wheel drive vehicle that may have a travel of 4" to 6". It also weighs about 1000lbs. more than most other four wheel drive vehicles. If you look down at your odometer and it reads 45,000 miles or an increment of 45,000 miles and you haven't changed your shocks, you are probably due.
If you are interested in updating your suspension to the newer anti-sway bar suspension (kit # 9273), the kit also includes new rear coil spring sand new shocks. This system greatly reduces body roll while providing a more stable ride. Atlantic British also offers original equipment and Bilstein performance shocks (kit # 9210 & kit # 9279).