The only reason to leave due to having a large stack is if there are several other deep-stacked players who you think are considerably better than you. Remember, if you are the only one at the table deep-stacked then your play doesn't change at all.

Quote Originally Posted by SoboQ4
How do you know when to stop playing...

when you think the other players stink yet YOU are the one loosing money...
you can play perfect and lose lots to terrible players running hot. it's no reason to quit.