In Basic D&D, IIRC, you checked morale the first time you downed a bad guy, the first time they downed a PC
or if the bad guys got reduced down to half their numbers. In other words, the monsters might flee if they took out a PC, or if they were likely to lose anyway. Morale didn't simply grind away at the monsters during the encounter.
One of the big perks of morale was that if you did break the enemy and made them flee (and to point out, the morale roll was for the whole group of monsters) was that you'd get a free attack with huge bonuses to hit as they fled, using the rules pg. 70 of the DMG. So when those goblins freaked out and ran it usually meant all of them getting hit and mowed down as they turn and fled.
I just spent several hours painting 15mm American WWII combat engineers.
I was being facetious.
Which is kind of silly. "Look, we killed one of them! Hooray! Now let's run away!"
Isn't morale now mentioned as being part of "hit points"?
3E definitely still had morale as a condition. Shaken, Frightened and Panicked where 3 "morale" conditions.
I didn't like any rules that used Will Saves against fear or morale effects. Or maybe I should say I dind't like that Fighters and Barbarians had low will saves? These guys go toe-to-toe with Dragons! They should have the best chance to shrug off these effects!

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.