Home prices are dropping like a stone. New-car sales are falling off a cliff. The stock market churns and churns.

Is your portfolio getting that sinking feeling?

When the economy's uncertain (or in this case, even more uncertain than usual), I look to add stocks with solid dividends to my portfolio. Specifically, I want sustainable dividends -- meaning, dividends that aren't likely to be cut or eliminated during economic crunches.

Even better are companies that are likely to raise their dividends, year in and year out. Stocks of well-managed companies with rising dividends tend to do very well over time, as you'd expect.

So how do we find these companies? By looking at history.

Dividend all-stars
Do you think a company that has raised its dividends every year for a decade might be a good bet? Think about what has happened over the past decade: The tech crash, wars, bubbles, economic crises ... a whole lot of good reasons for a nervous board of directors to cut a company's dividend payout.

But the companies I've chosen to focus on haven't succumbed to the temptation to cut dividends. All three raised their dividends, every year, from 2000 to 2009. (Some have already raised their dividends for 2010, as well.) And as you'll see, there are other reasons to take a closer look at each of these stocks, including high ratings from Motley Fool CAPS.

  • Regardless of your feelings about tobacco, Altria Group (NYSE: MO) is in many ways a model dividend stock. Tobacco and alcohol are recession-resistant, cash-generating businesses, and Altria has a long-standing policy of sending a hefty chunk of that cash to its shareholders. The company recently announced a hearty 8.6% increase in its quarterly dividend, its 43rd dividend hike in the past 41 years. With a dividend yield well above 6% and a four-star Motley Fool CAPS rating, Altria should be on any dividend fan's short list.
  • While almost everyone knows Altria, you may or may not have heard of Suburban Propane Partners (NYSE: SPH). Suburban Propane is involved in number of energy-delivery businesses, most related to (surprise) propane and fuel oil, but it's often overlooked because it's not a high-growth, high-glamour company. That's just fine with me: The company has doubled its dividend payout over the past 10 years while reducing its debt and increasing its cash holdings. Its dividend yield? A hefty 6.9%, following the company's most recent increase in July. If you smell an opportunity here, you're not alone: CAPS players have given Suburban Propane five stars.
  • Got Kleenex? Kimberly-Clark (NYSE: KMB) does, along with toilet paper and other supermarket staples. Toilet paper is about as recession-resistant as a business gets, and Kimberly-Clark comes with great management, low debt, and a dividend yield of 4.1%. The company's board gave its shareholders a 10% raise in February, making 2010 the 38th consecutive year in which dividends were increased. Like that track record? So do CAPS players, who have given Kimberly-Clark a top-of-the-heap five-star rating.

And now the caveats
These aren't formal recommendations, just pointers for further research. Any time you're planning on buying a dividend stock with long-term income in mind, it's essential to dig into the numbers and know what you're really getting. It's not unheard of for a company to be paying dividends when it really shouldn't: General Motors and Lehman Brothers were still paying dividends well into 2008, when both companies were already in deep trouble.

Even if a company is on sound financial footing, one can't always predict how management will handle its dividend over the long term. Even relatively healthy companies sometimes choose to cut or eliminate their dividends. Pfizer (NYSE: PFE) paid a fat dividend that won it many fans -- until it cut that dividend in half to help finance its acquisition of Wyeth in early 2009. After that cut -- pay attention here -- the company's stock price, already hammered by the economic crisis, fell sharply. Of course, if the price falls far enough, the dividend yield can start to look attractive again -- and Pfizer's is now 4.5%, high enough to draw some attention.

And, of course, sometimes disasters happen: BP (NYSE: BP) was one of my favorite dividend stocks for years, but public pressure and costs related to the Gulf of Mexico oil spill have put that dividend on ice for the time being. While there might be a value case for buying the stock, dividends aren't going to be part of it for a while.

Long story short: Don't skimp on the research, and don't put all your eggs in one basket, even if the basket has a 7% dividend yield.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.