How long do these ballasts/Bulbs last?
How longs a piece of string really?
I bought my HID's two years ago for about £70 from a UK ebay seller, and they have never given me any bulb warnings or anything. The kit looks exactly the same as the one's from the Far East so I expect it was just imported by an entrepreneur!
My ballast has just failed so it's lasted nearly two years, I can get one from China for £15 delivered which looks exactly the same as my existing one. I have chosen to spend £50 on two new slimline ballast's from a UK seller again. That way I can hide them out of the way and get two new ones, and will probably sell the one that still works on.
You certainly don't need to to spend as much as £120, kits are available from about £30 now, although I do accept that you get what you pay for.