This article is from the How to Start an Investment Program tutorial, author unknown.
Lastly, don't invest money in the stock market unless your personal needs have been met. If you're saving money to put down on a home or to purchase your first practice, the stock market is probably too risky a place to park your short term money. It's very possible that the market could go down when you need the money the most. Safer savings vehicles such as bank CDs or U.S. treasury bills or notes would be a better choice in this instance. In choosing one of these, you will never have to worry about your principle (the money you initially invest). It will always be there.