If you're like most Americans, Social Security makes up (or will make up) a substantial portion of your retirement income. And while too much exposure to stocks in retirement can be painful, having a portion of your nest egg allocated to high-quality dividend stocks can be a reasonable way to generate extra income. 

This is especially true if you follow some simple rules: Only invest money in stocks if you can hold them for the long term. Don't expose yourself too heavily to any single stock for income you have to have. Invest in high-quality companies with a substantial margin of safety in their ability to pay the dividend. Three that check all three boxes are TerraForm Power Inc. (NASDAQ:TERP)CareTrust REIT Inc. (NASDAQ:CTRE), and Starbucks Corporation (NASDAQ:SBUX)

Two seniors with unhappy expressions wearing work clothes.

You know what beats work? Dividend stocks. Image source: Getty Images.

Let's take a closer look at what makes these three stocks ideal candidates to supplement your Social Security income for many years to come. 

Under new management

TerraForm Power's asset base alone has made it an attractive investment for income seekers since it first initiated a dividend in late 2014. However, a history of overreliance on debt to fund new projects, while paying out the lion's share of cash flows in dividends, left the company with a bloated balance sheet and high expenses. This played a big role -- along with the bankruptcy of former parent and sponsor company SunEdison -- in the company not paying a dividend for almost two years before reinstating it in late 2017. 

But going forward, there's a lot to like about TerraForm. It continues to own and acquire great assets that should generate steady, predictable cash flows for decades to come, but management should be a real strength now. Global asset management giant Brookfield Asset Management (NYSE:BAM), took control of TerraForm in late 2017, and immediately brought in a team of experienced Brookfield executives to right the ship and run the company going forward. Just as importantly as having the right people in control, they are set to follow the Brookfield model, which has proven incredibly successful for many years

Wind turbines and solar panels in a utility-scale project.

Image source: Getty Images.

The key aspect of this operating model are a rigorous, disciplined approach to capital management and cost containment. While the company will continue to utilize debt and common equity sales to raise capital to invest in growth going forward, it will also retain more of its cash flows to utilize as well. The result will be a company that's less reliant on the whims of the stock and debt markets to raise capital, which should lead to a healthier dividend and lower risk over time. Ideal considerations for retirees. 

With a 6.5% dividend yield based on the company's 2018 dividend target of $0.76 per share, TerraForm is an excellent high-yield income investment for retirees to consider. 

You're the reason this dividend stock could be a huge winner

With a dividend yield of 4.8% at recent prices, real estate investment trust CareTrust REIT Inc. is getting a lot of notice from investors looking for a nice paycheck. And with its focus on senior healthcare and housing facilities, the company could be poised for 20-plus years of growth. 

This is because we are still early in the baby boomer generation's transition into retirement. Between now and 2029, when the last boomer turns 65, around 3 million boomers will reach retirement age each year. That's another 33 million people who will retire over the next 11 years, adding to a burgeoning senior population in the U.S. that will reach 80 million by 2030. That's more than double the 65-plus population when the first boomer turned 65. 

CareTrust is well positioned for a lot of growth. With just under 200 properties in its portfolio at present, it has more than doubled in size since going public in 2014, allowing it to increase its quarterly payout by 64%. 

CTRE Dividend Chart

CTRE Dividend data by YCharts.

Much of its growth so far has been via acquisition, consolidating an industry made up substantially of small single-location or regional owners with a handful of properties. And with a strong network of healthcare partners who operate the facilities under long-term (often a decade or more) leases, its cash flows are very predictable. 

For someone looking to supplement their Social Security for the long term, CareTrust should prove an ideal long-term income investment worth buying now and holding for many years to come. 

The power of a global brand

It may only yield 2.93% at recent prices, but Starbucks' prospects as a dividend growth stock shouldn't go unnoticed even for income-seekers who can buy and hold for the long-term. 

To start, the company's history of dividend growth is remarkable. Since paying its first dividend of $0.05 per share (split-adjusted) in 2010, Starbucks has increased it every single year, growing the payout 620% in less than a decade. 

SBUX Dividend Chart

SBUX Dividend data by YCharts.

Furthermore, it maintains an enviably low payout ratio, retaining a substantial amount of earnings to reinvest. Even after a recent 20% increase in the payout, Starbucks will still pay out less than half its earnings in dividends. 

And while Starbucks has numerous growth drivers, including digital ordering and rewards, and store expansion with its Reserve stores and global growth, it doesn't have to hit it out of the park to be a wonderful source of growing dividends for retirees for many years to come, particularly with shares trading at current valuations. At recent prices, Starbucks trades for less than 15 times the low end of company guidance for 2018 earnings per share. 

To put it in further perspective, you can buy Starbucks today at valuations and a yield that's very close to twice as attractive as you'd get even one year ago. For such a high-quality business, dividend seekers should put it high on their lists today. 

Jason Hall owns shares of CareTrust REIT, Starbucks, and TerraForm Power. The Motley Fool owns shares of and recommends Starbucks. The Motley Fool has a disclosure policy.