"...at some point during a continued decline you must decide: “This has gone through the Support; I should sell and take a small loss now, rather than risk a more serious loss.” And the most painful part of all is that sometimes, the moment you have sold and taken your loss, the stock will come to life and complete what would have been an extremely profitable move. You might just as well prepare yourself for this sort of disappointment; for it will happen to you. But to avoid nights of pacing the floor and days of worry, you should decide, at the time you make the original commitment, just how much leeway you are prepared to give the stock. Then you will not be tempted to put off a decision from day to day if things are not going the way you hoped. "
- Edwards & Magee