You replace them when they stop working. They stop when they stop.
No, it cannot. But the belt connecting them together can.
In my experience that is a failure of the alternator or something connected to it.
alternator belt broke it drives the fan
lack of water
What would make your speed odometer stop working after putting an alternator on? 2005 Chevy Malibu
broken bulb
Windshield wipers are an important safety feature on cars. They stop working when their motor goes out, or when the blade is too worn out.
Bad electrical connections.
the common cause why the light is on is that your alternator is not working well,try to have your alternator checked .may be the carbon brush is already worn out.
Electrical Failures But Engine Continues to OperateAlthough it is possible, it is not very likely because with an alternator failure, the battery will become discharged, and eventually will "kill" the ignition and thus the engine.This sounds more like a fuse or relay failure.
It is important to know what causes things to stop working within a car. A blown fuse or bad wiring can cause the key and headlight chime to stop working.