I've had an ancient Parker 51 for a good decade or so now which I use almost daily, that originally belonged to my great-grandmother.

I'd expect there to be a reasonable amount of variation in how long these pens last due to differences in usage, machining tolerances, ink types and materials - though mine has done very well considering how many times I've chucked it into a bag, dropped it on hard floors, etc. (I've probably just been lucky so far).