i had a bunch of leds that didn't work at all from cointakers few months ago, it was a defect.
didn't ask for a refund or anything, was about 20 in total. 10 white, 10 red.
i think i changed, about 10 leds in all my machines in the past 2 years, i think it's good, most was because socket went lose, the glue was bad, didn't hold in the socket.