When I am playing on a table that I am beating and thinking it might be time to call it a night, I will ask myself some questions.
1. Am I getting tired or bored? Not paying as much attention? If so - time to go.
2. Has the table changed and are the fish gone? If yes - leave
3 One habit that i have learned about myself happens when I am up what I think is a "successful" amount. Maybe I've doubled my buy in or just done well. Am I still playing aggressively or have I gotten into a pattern of "protecting my winnings"? If I am playing "not to lose" - it is time to go.

On the losing side - two hard questions.
1. Am I the fish here? Not easy for me to admit, but important.
2. Have I started to play hands I wouldn't normally play, trying to catch up?
If I can't tell myself a resounding NO to either of these questions then it is time to leave.

Just my two cents worth - I hope more people jump in on this topic.

The right questions to ask oneself, I believe. I'll add one, which I find myself doing?

Am I giving it back?

I do this. When I'm down, I tend to tighten up. When I'm up, I'm in danger of playing too loose. I have to watch this, always.

Basically, I ask myself, am I still enjoying the game? If I am, I stick around. If I'm not, gotta go. The hard part is not asking the question a second and third time.

I try to check the average pot for the table every 20 minutes or so, if you multitable it's easy to be oblivious to the fact that everyone has tightened up, you should be going to war against your opponents, not the concept of a session or how much you think you deserve to win.

Especially when 2 or 3 tabling I also try to keep an eye on myself, as to whether I've tightened up too much, quite a common side effect for me.

Molina

musicman,

There's no blanket answer to your question; it depends on why you're playing. Are you playing for fun? If so, the question becomes, "Am I still having fun?" If you're playing for money? If so the question becomes, "Do I still have a positive EV?" (Ok, it's not as simple as that - you could forgo playing now when you have a pos EV because you'll have a greater EV later but will be too tired if you continue now but you get the idea.)

Anyway, you have to understand your reasons for playing before the question can be answered.

TUP

If youre playing online and you are a solid winning player at your stakes, then its going to be very rare that you will ever be in a -EV situation soley because of the other players at the table.

Its not like Hanson, Lederer and Negreaunu are going to come strolling into my $400NL game at Party.

So therefore, I leave when I get tired, feel like doing something else, my wife smacks me for playing too long..etc...

I never quit because Im up too much or down too much or anything like that.

Another potential point to stop while you're ahead is if you play quite tight and have gotten big wins with big hands and your opponent are fold to raises because they now know you'll have the goods. If you simply aren't getting callers when you want them then it's not a bad time to close the session.

I know the argument to this either 'your game shouldn't be that predictable' or ' now's the exact time to loosen up and really push your opponents' and I do agree, but depending on ones experience and comfort with a looser style this may not be recommendable.

Then again, often when I have a big stack and I'm still playing tight, some opponents seem to forget the monsters you've won with and convince themselves you can't possibly have a hand again.

So, my definitive answer is, it depends (never heard that before!).

Molina

I always leave when im tired.. when im tired i dont have enough time to make money back if i lose it. I always like to leave a positive note. I leave when my luck as at it's best.. and it sometimes continues on to the next day.. it's great .. but if you dont mind leaving after a loss then leave whenever you want.. play till you drop : ).. one time when to quit is when you start gettinf frustrated/anxious to make money.. you have to identify when these spots happen and pull away.. sometimes i tell myself im not but i really am.. hard to tell

I swear, whenever I'm on the phone talking to a girl trying to go on auto-pilot, I always lose! and it always spills into the conversation and force myself to leave the game