I want to know the answer to the following question:
What is a classification used in LED lighting to describe how much usefulness it will receive?
All the background I'm provided with is that "To quantitatively classify useful lifetime in a standardized manner it has been suggested to use L70 or L50, which are the runtimes (typically given in thousands of hours) at which a given LED reaches 70% and 50% of initial light output, respectively.". Is that enough to answer the question?