Obviously I haven't really read my SB-800 manual. I learn something new every day, which is a good thing. I looked up (on wikipedia, that repository of all knowledge :wink what electronic flash photography generally uses, and whaddya know, electric arc through xenon gas. That makes sense about occasional recalibration and replacement.Agree.
Although if you read the SB-800 manual, Nikon recommend an annual check, recalibration - and will if necessary, replace the flash tube (which is the main component that 'wears' - the other components are just fairly highly stressed (by design due to the nature of a speedlight))