What I have learned the hard way is no matter how smart, sophisticated or experienced a trader is, all successful traders that I follow have one common theme: When they realize they have made a mistake, they exit, fast, no excuses, no rationalizing, no debate, no wringing hands, exit, done. That is the sign of a professional in my opinion.
Without a trading plan, the market will sit silently and let you crank out numerous small gains and wait, sit and wait patiently for that one day, that one trade that takes it all back and then some. The only thing that stands in the way of your exit is your pride and ego and at the end of the day you have left neither your pride, your ego, or your money...
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"You got to be able to get out while the getting out is good...You can't ignore an error. Once you realize that you have made an error, the best thing is to get out of that error and start again, fresh, and that is what a good trader does." Leo Melamed
As far as averaging down on a losing trade, in the 1987 PBS documentary "The Trader", Paul Tudor Jones has a note on his wall: "Losers Average Losers"
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