96 Disco SD
#1
#2
I would replace it only if it is plugged up. One of the main reasons for the charcoal canister to fail is contamination with liquid gasoline. It is important not to over fill the gas tank. Some people have the bad habit of keep pushing gas after the pump shuts of the first time, that could make gasoline to get in the breather line and go to the canister. Other than that, they last for a LONG time.