I play for hours if the games are good. Basically, if you feel as though you have a significant edge, you shouldn't leave the game.
i find people tend to overvalue their own edges a little too much thou
your right clearly but if you really are tired or notice your not playing your A game or B game just stop regardless of how long
rarely there is going to be that whale that is spewing off 15 buyins over 2 hours
and if you limit your sub optimal play it will keep your win rate high per hand played and make you move up a little faster
clearly all of this is a personal thing but over the last few years i have realized that the amount of money i have lost simply because i didnt leave when i knew i should is pretty big
same thing happens in regging for tournies when you know you dont have time to play it out or you will be well into like 4am with work the next day it just isnt worth it long term