I've heard a theory bandied about in the last few years regarding cheap incandescent lamps and their extremely short life-spans (some I've heard are measured in milli-seconds).
What was being said, was that the reason behind the failure is caused by the glass envelope of the bulb not being evacuated properly and there still being air inside the bulb.
Now, everyone knows that a light-bulb filament needs to be in a pretty good vacuum otherwise it's life is pretty short-lived (we even tried this at Night School).
I don't know how much one can actually read into such a theory, but it does make you sort of wonder.
