Why do the led products need ageing testⅱ?

Why do the led products need ageing testⅱ?
We have touched upon subjects from a variety of led product and we’ll explain everything When the design led product. we are fully prepared for this. but Why do the led products need ageing test ?The theory of product quality is explain For all.
Product quality prone to bias In the initial stage of using and end stage of using. The product server time is over in end stage of using.we have no idea for it end stage of product. initial stage of product(include from raw materials organization, production, packing to shipment.) It has shown that the step is controllable, observable, and its stability may be guaranteed.so We should not only strictly limit its production , but also to do ageing work well.the customer can get excellent led products.