In honor of Worldwide Invest Better Day (WWIBD), we at The Motley Fool are recapping our "13 Steps to Investing Foolishly" — steps you can follow to become a better, more Foolish investor.

In the following video, Chief Investment Officer Andy Cross explains the importance of Step #10: Don't sell too soon. Selling a stock should be just as big a decision as buying, and our preference will always be investing in great businesses for the long term.

That being said, certain situations can tip the balance in favor of selling, and Andy identifies five specific circumstances that may indicate it's time to unload.

If you remember just one thing, though, it should be this: Fear is not a reason to sell! When the Dow Jones Industrial Average (INDEX: ^DJI) fell off a cliff a few years ago, lots of investors were terrified, and pulled out their investments after taking 15% to 20% in losses. Instead, investors should have taken a more level-headed approach. Fluctuations, large and small, are part of investing. When the market headed lower, the drop created some of the best buying opportunities in a generation. The patient and intelligent investor made out like a bandit, while the fearful got burned. Don't let this be you! Watch the video to learn exactly what constitutes an appropriate time to sell.