A system for indicating an end of a life cycle time period for a device which may include a sensor device or detector for measuring an environmental condition. A control device communicates with the device and includes a programmable timing mechanism for measuring a life cycle time period. The control device initiates an end of life cycle indicator such as a fault message after the life cycle time period has elapsed. The life cycle time period may be measured from a date of manufacture of the device. The life cycle time period may also be measured from a date of installation of the device when the date of manufacture of the sensor device is unknown. In the case of sensor devices or detectors an environmental condition for measuring by the detector may include carbon monoxide levels in an enclosed area where the device is a respective carbon monoxide detector.