Every poker player faces the dilemma of knowing when to walk away from the table. If you want to become a winning poker player you must know when to quit, you must know your limitations and recognize when you're on a bad streak so you can bail out a game before you put serious dents into your Bankroll.
The way I see it is, if you're playing good solid poker then there is no need to quit, you should not head into a game saying "I am going to walk once I make $ 900" or ill leave if I lose 2 buy ins. There is no need to set limits on how much you can win or lose and use that to determine when you should stop playing. Firstly it disposes your mental approach to the game and secondly you are potentially leaving a lot of money on the table if you are playing Good Poker.
There will be times when you are playing solid poker though your opponents keep sucking out on you, in this situation there is no need to quit the game, you just have to be patient and wait. The tables will turn suddenly and your perseverance will be rewarded, I've lost $ 1200 in a session and then re-bought with another $ 400 only to see myself make in excess of $ 5000. Therefore if I had walked after I lost 3 buy ins I would have never given myself the chance to reap those extra profits.
On the other hand if you can not emotionally handle a few bad beats or go on tilt immediately after your opponent hits his running flush on the turn and river, then I recommend you quit before sending your Bankroll to the cleaners. Also if your bankroll has been seriously injured and you can not take anymore hits then you should seriously consider walking, regardless of whether your playing good poker or not, after all you can not control the cards.
Now if you're on a lucky streak or on a rush in poker, then the game is good and you're making good money, in this situation you should always continue playing. Poker has a lot to do with confidence, and if you're on a winning streak your confidence is soaring through the roof. You'll tend to make more aggressive decisions, be able to read your opponents better, place more traps and punishment people for drawing. Basically, you'll be running the table.
A losing streak is not the only thing that will affect your mental state and sabotage your game. If you're tired and need rest, you need to stop playing. It does not matter if you're winning or losing, if you begin to feel fatigued and start making poor decisions you should leave the table. Whenever you're at the poker table make sure you have ate and are alert, if you're tired you'll start making rash decisions and call with more marginal hands.
In conclusion you must always bring you¡¯re A game to the poker table, in order to do so you must feel good, both mentally and physically and always be alert. If you begin to feel tired or become emotionally affected and you sense that you're concentration is slipping, step away from the table and take a break. Remember, the Game is not going anywhere.