Here we go.
If you are a "grinder", you play. You put in the time, play
hands. It is a long-term game. Think of it as a never ending session.
If, you are trying to build a
bankroll, I suppose leaving after reaching whatever amount of dollars, say 100 BB+, is acceptable, only because it represents a larger portion of your bankroll (that you are trying to build).
If I go on some sick heater, and run up a 500 BB+ stack, and the game is wild and deep, I might just book that win at some point before we get cold decked for some insane amount of BB, but that may or may not be optimal. I suppose the real pro would stay if the game was good.
In my opinion, play as long as you are playing A game or near A game, if the game is good, if you have a clear skill edge on opponents, etc. Play as long as conditions are good to play.
That's my opinion.
I was up over about 240 BB the other day, and went to dinner. I came back from dinner, and lost 100 BB in like 30 minutes.
I stayed. I ended up making an additional 260 BB or so, after we lost the 100 BB after dinner. Grand total for day like +409 BB.
So, you can see how it pays to stay in a game that's good, when you are playing well, and have an edge. This example of course is a pretty good result, and it may backfire sometimes and you lose. But, if you truly are a winning player, you are making money over the long term so it really doesn't matter one way or the other (if you are a proven winner).