Honestly, I don't know when mine failed and I have had the car for 2 years. It is 12 years old now. I would guess that if it's an LED problem, that UV and heat probably have something to do with it. Living here in Okinawa, Japan it is subtropical and the heat, humidity, and corrosion as well as UV are very strong here. I replaced sun damaged parts 10+ years ago on my R32 GTR only to have the sun damage the replaced parts (seals, weather stripping, wiper arms, rubber trim, plastic interior pieces, etc.) again. So, that's where I'm coming from if that helps define my statement of a new light failing again at some point. In this environment, it will be sooner than later and not if, but when.
As far as replacing parts, I go to the Nissan dealer out in town and with the yen getting weaker against the US$, the parts prices are getting more reasonable.