You buy an LED bulb. The box says "Life: 50,000 Hours." You do the math. If you use it 8 hours a day, that is 17 Years. But wait. LED technology is new. No one has been testing this specific bulb for 17 years. So, is the manufacturer lying? No. They are using Science. specifically, a standard called IES LM-80. LEDs Don't "Burn Out" (Usually) Old tungsten bulbs would go POP and ... https://cometenvirons.com/