Understanding and quantifying the behavior of a single LED, and calculating how this will affect a system with multiple LEDs, are crucial if lighting companies are to set their system warranty level correctly and assess the cost of failures potentially occurring within the warranty period.

Power LED manufacturers claim many advantages for their products over traditional light sources; one is their presumed ultra-long life. In applications that cannot tolerate failure, or where maintenance and repair are difficult or costly, long operating lifetime and extended maintenance cycles are attractive, even when balanced against relatively high purchase costs.

Luminaire manufacturers, and lighting designers and specifiers, have generally been reassured by the claims from LED manufacturers that their devices will typically operate for 50,000 hours. But in fact, the claims of long operating life for LEDs, as for any component, only apply under certain conditions. What is more, LEDs can and do fail in rare cases