You've worked long and hard to earn what you have today, and you've built a sizable nest egg. Now it's time to begin thinking about how to best draw on your assets to fund your retirement.

You want to include stocks in your diversified portfolio because you know that they're one of the best ways to grow your net worth over time. But you don't want to needlessly jeopardize the wealth you've acquired by choosing stocks whose value evaporates. So which stocks are best?

What you're seeking are the stocks of stalwart businesses that provide essential products and services. Businesses that operate in industries that are sure to still be around decades from now, and that are likely to enjoy increasing demand over time. Fortunately, there are some excellent stocks that fit this description. Here are three of the best available in the market today.

Image Source: Waste Management

The garbage king
Few services are more essential than waste collection. Modern society simply couldn't function without it. That makes industry leader Waste Management (WM -0.83%) the type of defensive investment that's well suited to older investors.

The aptly named Waste Management is the leading provider of waste collection and recycling solutions in North America, serving more than 21 million customers in the U.S. and Canada. The company owns the largest network of recycling facilities, transfer stations, and landfills in the industry. This creates an enormous competitive moat around Waste Management's business, as the not-in-my-backyard attitude among many homeowners and notoriously difficult approval process for new waste facilities makes it unlikely that competitors will be able to displace the garbage king.

With its revenue streams well protected, Waste Management is able to reward its investors with share repurchases and a steadily rising dividend -- both of which help to support its stock price. And with population growth expected to increase demand for waste collection services in the decades ahead, Waste Management's 13-year streak of consecutive dividend increases is likely to extend for many more years into the future.

Image Source: Johnson & Johnson

The healthcare titan
Healthcare is another essential industry, and it's one in which multiple long-term trends should fuel rising demand:

  • Population growth means more people will need access to proper healthcare
  • An expanding global middle class will make healthcare more affordable for millions of people around the world as their purchasing power improves
  • And increasing life expectancies will lead people to depend on health products and services for longer, and likely more often, than they do now

Industry colossus Johnson & Johnson (JNJ 0.23%) is particularly well-positioned to profit from these megatrends. The conglomerate combines the world's most comprehensive medical devices business, the fifth-largest pharmaceuticals business, and sixth-biggest consumer health business into one massive, $280 billion entity. Such a broad global footprint means many of the dollars that will be spent on healthcare products and services will flow into Johnson & Johnson's coffers, and ultimately, into the hands of its shareholders.

But Johnson & Johnson is not resting on its laurels and simply waiting for a rising tide to lift all boats. The company is investing aggressively in research and development, which has produced a well-stocked pipeline of promising new drugs. Management is also on the hunt for acquisitions that could bring additional elements of growth and further strengthen J&J's drug portfolio and medical technologies.

All told, Johnson & Johnson has rewarded its shareholders immensely since its initial public offering in 1944 -- a trend that seems likely to continue for decades to come.

The banking giant
As much as people seem to dislike the financial industry, there will likely always be a need for the type of banking services that Wells Fargo (WFC 0.03%) provides.

The company is widely considered to be one of the most well-run banks in the world -- if not the best. Its disciplined underwriting standards, conservative culture, and diverse business lines have helped Wells Fargo perform well through even the most difficult economic periods. For example, during the financial crisis of 2008-2009, Wells Fargo continued to deliver solid profits even as many of its less-disciplined competitors collapsed.

This proven ability to operate in all market environments has made Wells Fargo a favorite investment of legendary investor Warren Buffett, who once said, "If I had put all of my net worth in one stock, that would be the stock."

Of course, neither Buffett nor I would ever recommend that an investor place all of her net worth into any one stock. And I should note that Buffett's comment was made in 2009 in regards to Wells Fargo's stock price during the depths of the financial crisis. Still, the statement highlights Buffett's conviction in his investment in Wells Fargo and his respect for the bank's powerful competitive advantages, including its ultra-low-cost deposit base and superior ability to monetize its client relationships via its broad array of services. Importantly, these aspects of Wells Fargo's business have grown even stronger in the years since Buffett's remark.

Warren Buffett has owned Wells Fargo stock for 25 years, and there's no evidence to suggest that he plans on selling his holdings any time soon. I can understand why, as the all-weather banking titan seems set to deliver more gains to its shareholders in the year -- and quarter century -- ahead.