In times of war a good commander understands that there are times that one should retreat. Retreating is not as glorious as the all mighty attack, but retreating is what smart commanders will do when they are overpowered. This same idea applies in the game of chess. There are times when one must retreat in order to win the game. A failure to retreat could cause you to lose the game. Remember the saying that it is not important to win the battle, but to win the war. Look at the big picture in your chess game just as a military commander looks at the big picture in a war.
A smart military commander always has an option for retreating. A good chess player needs to keep this retreat option available also. One mistake many chess players make is that they do not leave an open square for a valuable piece to retreat to. This is a fundamental mistake. While it is difficult to remember this in a game it is vital to winning. Leaving a square to move a piece back to, if it comes under an overpowering attack, is always a smart move. Giving up a primary piece without a trade is a poor move. Most chess players attempt to cover every piece with protector, or a piece that will capture the attacking piece if they lose a primary piece. But what happens if your opponent has a double attack? Then you must be willing to retreat in order to stay at least even with your opponent in the number of pieces you have.
The second part of this is that you must be willing to retreat when the time is right. Being overly aggressive and losing pieces to your opponent out of frustration hands the win over to your opponent. Chess players must be willing to play the retreat in order to win the war, instead of focusing on the battle.