Does dimming LEDs decrease their lamp life?
It has been observed that when some fluorescent lighting systems are frequently dimmed, they might exhibit reduced reliability and lamp life. This is not the case for LEDs. Life and light output degradation are determined largely by the junction temperature, with higher temperatures resulting in reduced life characteristics. Since dimming, either by reducing current or by pulse width modulation, results in lower overall junction temperatures, it will have no negative impact on LED life; it might even extend life. (See also What is the life of LEDs?)