Useful life has been defined as the number of hours an LED device can operate until it emits only a certain percentage of its original lumen output. For general illumination applications, vision research suggests that 70 percent of original lumen output is the level where end users begin to notice a drop in light levels. This metric is indicated as L70. The Illuminating Engineering Society of North America (IESNA) published LM-80-08, IES Approved Method for Measuring Lumen Maintenance of LED Light Sources. Our LED lamps have been tested for long-term lumen maintenance consistent with LM-80 methods to demonstrate L70 life after more than 6000 hours of testing and got the number 50,000 hours under normal operating conditions. Also the performance of all of our products is verified by accredited independent 3rd party laboratories. Please note, any initial condition or parameter change will affect the useful life of LEDs in different ways.