Ah, thanks, I forgot that. I'd hardly call one throwaway line in one show, "every show that takes place in the 23rd century wants to use it as some Holy Grail"!Discovery referenced it in connection with Pike's Enterprise. It was explained at the start of season 2 that the Enterprise was uninvolved in the Klingon War because it had been out on the frontier conducting its 5-year mission.
Ah, interesting; I didn't know that.That assumption was around long before the Okudachron. References to Constitution-class ships having 5-year missions as a standard date back at least to the 1979 Spaceflight Chronology. IIRC, the fanzine article collection The Best of Trek 6 from 1983 reprinted a fan chronology (based largely on the SFC) that mentioned Pike having two 5YMs on the Enterprise.