I've got a Badger 350 single action airbrush that I've used for 25 years - I figure I've gotten my money's worth out of it. ;)
I've got both medium and fine nozzles for it, but very seldom use the fine nozzle except for free-handing feathered camoflage schemes.
I strip it and thoroughly clean it every time I use it, which I think has helped it to last as long as it has.
I recently bought a Badger 150 dual action airbrush, but am still learning how to use it.
Mark