Defibrillators save lives - every time the East of England Ambulance Service is called they have a map of registered defibrillators to refer to, finding the nearest if needed. They tell us if the unit has been deployed, it's then removed from the list of available units. Once the unit has been returned to the cabinet we physically check it has pads, what the battery life is (it depletes with use), check both the unit and the cabinet for damage or faults, only then is it returned to the "live" map, making it available for others if needed.