The CV joints on the Land Rover are made to last a long time.. given highway use. The cages are made of VERY hard steel, and when subjected to potholes and off-roading, they often break. Replacement is not very difficult but can be expensive. Genuine units are easily available, but some aftermarket units (like the one from Great Basin Rovers) are made of a slightly softer metal that offers better performance for vehicles used off the road.
The procedure can be found directly from the Shop Manual.