Dividend stocks make for exceptional investments. But unless you're relying on the income to live right now, you're making a huge mistake by not having it automatically reinvested back into the underlying stock via a dividend reinvestment program, or DRIP.

In the following video, Motley Fool contributor John Maxfield looks at how this simple adjustment completely changes the nature of an investment in Wal-Mart (NYSE:WMT) and McDonald's (NYSE:MCD) over the past two decades.

John Maxfield has no position in any stocks mentioned. The Motley Fool recommends and owns shares of McDonald's. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.