Sometimes, you're better off walking away from what seems like a great deal. If a person offers to sell you a Rolex for $50, for example, walk away. There are some dividend stocks with high yields that you shouldn't just walk away from -- running away would be the smarter choice.

But there are some stocks with dividends yielding more than 4% that I think are solid picks for long-term investors. Here's why Brookfield Infrastructure Partners (NYSE:BIP), Iron Mountain (NYSE:IRM), and Seagate Technology (NASDAQ:STX) fall into that category.

Five ascending stacks of coins with blocks on top of each stack spelling out yield

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Brookfield Infrastructure Partners

Brookfield Infrastructure Partners currently offers a dividend yielding nearly 4.6%. In 2017, the global infrastructure giant gave investors even more to like than its nice distributions: Brookfield stock soared nearly 34%.

But why is Brookfield Infrastructure Partners still a good stock to buy? My answer is to look at the company's various operations. Brookfield owns cell towers, energy transmission and storage businesses, ports, railroads, toll roads, and more across North America, South America, Europe, and Asia. These businesses generate consistent cash flow. Even better, the company can hike its prices on many of these assets as inflation increases.

I also like Brookfield's plans for future growth. In November, CEO Sam Pollock listed three areas that Brookfield would focus on: data infrastructure (such as cell towers and telecommunications networks), municipal infrastructure (including central heating and/or cooling systems that serves multiple buildings), and Asian markets. 

The company thinks that it can deliver 6% to 9% annual growth in funds from operations (FFO) in the coming years. Assuming Brookfield achieves this goal -- which I think it can -- that should translate to similar growth in the dividend distributions. 

Iron Mountain

Iron Mountain's dividend yield stands north of 7.4%. The company expects to grow its dividend by 4% annually over the next few years. 

When it comes to records storage and information management, Iron Mountain is in a league of its own. The company has more than 225,000 customers, including a whopping 95% of the Fortune 1000. Although many large customers do business with Iron Mountain, no single customer accounts for more than 1% of total revenue. 

Iron Mountain is also getting into the data center business in a big way. In December, the company announced that it was acquiring the U.S. operations of Arizona-based colocation data center services provider IO Data Centers for $1.3 billion. 

Although the stock has fallen so far in 2018, in part due to the stock offering and debt offering the company initiated to fund the IO Data Centers deal, I like the prospects for Iron Mountain over the long run. Organizations continue to churn out more records and data that need to be stored. Iron Mountain appears to be in great shape to grow from increasing demand in these areas.

Seagate Technology

Seagate Technology pays a dividend that currently yields 4.2%. The stock only gained 9% in 2017, but so far this year, it's up more than 40%.

There are a couple of factors behind Seagate's impressive run in recent months. First, the company reported solid second-quarter results in January. Second, Seagate appears to have been an early investor in Ripple, the cryptocurrency whose valuation has skyrocketed.

I wouldn't prioritize Seagate's Ripple investment high on the list of reasons to buy the stock, but it's a different story with the underlying drivers behind the company's good quarterly update earlier this year. Demand is increasing for hard-disk drives (HDDs) from data centers looking for cost-effective storage. Seagate continues to move toward making higher-capacity storage -- exactly what data centers need.

At the same time, Seagate is also positioning itself to be more competitive in the solid-state drive (SSD) market. The company partnered with Toshiba in October 2017 in a long-term supply agreement for NAND flash memory chips that can be used in SSDs, HDDs, or hybrid solutions.

Favorite of the group

All three of these high-yielding stocks should perform well over the long run. My favorite, though, is Iron Mountain. I like the company's near-monopoly status in its market. I also think its move into data centers will pay off. And who wouldn't like that mouthwatering dividend?

In addition, the current economic boom will subside sooner or later. Iron Mountain's business should allow the company to ride out a recession better than most, since companies will require records and data storage regardless of how the economy is performing. Overall, this stock appears to be a great pick for income-seeking investors.