^^Isn't that universal in televised entertainment, though? At least careers in a fictional Starfleet are more easily handwaved than careers in, say, NYPD or USAF or UCLA.
You're right. Just this past winter, during my re-watch of Gomer Pyle, U.S.M.C.
, in a handful of episodes, Sergeant Carter was said to have been in the Marines for fourteen, thirteen, fifteen and eighteen years!