Stonerdanswered grow question 4 years ago If its a good quality LED lighting with proper diodes (Samsung LM301H/B for example) then it can last you for about 4-5 grows before starting to degrade/diminish which is over a year. Unlike the cheap blurples for 40-50$ that can last for a cycle or two before losing strength (not as efficient as high quality lights altogether-not worth it in my opinion).
This is from my experience with these LEDs.
Hope this helps! Good luck and happy growing :)