A Little Complacency Is A Dangerous Thing
Do not get complacent about an open position. Always know where you are getting out, even if the point is far removed from the current price. Also, an evolving pattern contrary to the trade may suggest the desirability of an earlier-than-intended exit.
–Jack Schwager, from Schwager on Futures: Technical Analysis (1996, John Wiley & Sons, New York).