I have used lights for the entire 25 years I have had chickens. Chickens are going to lay less each year regardless. I do often replace mine every 3 years, but have kept pets that laid until their deaths at 8-10 years old. I start my lights around August 15th when the light here goes below 14 hours & ramp it up every couple weeks. The girls don't all molt at the same time, so some are laying & some are molting. YMMV