This is a real problem and I suffered from this for years. But This is how I controlled myself from over trading: I used to shut down the computer after a fixed number of trader, and day after day I convinced my mind not to turn on my computer before market closing time. Now after months of practise I have trained my mind not to take any more trade even if I am sitting in front of the terminal once the daily limit is reached. Now my impulse to always remain in a trade is controlled.