The present invention provides methods and devices for determining end of life of a light fixture by comparing the light output of a control LED of the fixture with the light output of an illumination LED of the fixture. The control LED is energized for a short period of time for the purpose of measuring its light output. The illumination LED is energized for the duration of time of the light fixture itself. In this way, the amount of degradation of the illumination LED can be determined by comparison with the control LED. If the light output of the illumination LED falls below a threshold level, actions may be take, such as, for example, sounding an alarm.