Retirees are often in need of two things above all others when it comes to investing: safety and income. Safety, because without additional funds to invest from a job or business, a major investment loss can be difficult if not impossible for a retiree to overcome; and income, as dividends comprise an important part of many retirees' budgets.

Safety is best achieved through strong competitive advantages that help to insulate a company's revenue and cash flow, which it can then pass on to shareholders as income via dividends. Fortunately, there are some stocks that excel in this regard. Read on to learn about two of the best.

Image source: Home Depot.

The home improvement superstore

Retail is not often considered a defensive industry. Consumer preferences change often, and competitive advantages in this arena can be fleeting. That makes what home improvement chain Home Depot (NYSE:HD) has accomplished over the last four decades even more impressive.

Since its establishment in 1978, Home Depot has been built upon a foundation of excellent customer service. It's this commitment to service that's made the company a mecca for the do-it-yourself crowd, as well as an important resource for professional contractors. Perhaps more importantly, its dedication to quality service has also insulated Home Depot from the relentless assault of online rivals that's ravaged many other brick-and-mortar retailers.

With more than 2,200 stores in the U.S., Canada, and Mexico, Home Depot is the world's largest home improvement retailer. Yet with less than a third of the do-it-yourself market and only about a 10% of the professional market, Home Depot still has room to gain additional market share. And with its store count expansion largely completed in the U.S., the company is able to pass the majority of its cash flow on to investors in the form of share repurchases and a steadily rising dividend.

With its competitive position well secured, healthy free cash flows, and value-creating capital returns, Home Depot is a low-risk income stock worthy of consideration by retirees.

Image source: Apple.

The tech titan

Like Home Depot, investors often mistakenly identify Apple (NASDAQ:AAPL) as just a hardware company. Yet the company's broadening array of services is becoming an increasingly powerful competitive advantage. Cloud services such as iTunes, iCloud, Apple Pay, and, to a lesser degree, Apple Music, all help to lock users into Apple's ecosystem. Once people have all their music, apps, and documents stored in Apple's cloud and synced perfectly across all their Apple devices, they are much less likely to switch to a competing platform. Often it's just the opposite, with this stickiness leading to Apple's famed "halo" effect, whereby a consumer is more likely to purchase another Apple product once they've entered the company's ecosystem. In turn, that leads to more App Store and iTunes purchases, a trend that can be seen in the impressive 24% year-over-year increase in Apple's services revenue in the fourth quarter.

Additionally, Apple's most important product -- the iPhone 7 -- is off to a strong start. My Foolish colleague Daniel Sparks notes that 18% of iPhone buyers in the first month of iPhone 7 availability switched from Android, according to a recent Consumer Intelligence Research Partners study. In fact, CEO Tim Cook said in the company's fourth-quarter earnings call that Apple saw more customers switch from Android to iPhone than ever before in 2016. It doesn't hurt that archrival Samsung can't keep its phones from catching fire.

With the iPhone continuing to lead the way, Apple's product lineup is as strong as ever. The company's services business is booming. And Apple's gargantuan cash flows -- to the tune of more than $16 billion in operating cash flow in Q4 -- allows the company to reward its shareholders with a growing dividend income stream. As such, retirees may wish to consider taking a bite of some Apple shares today.