When you're in the market for dividend income, it's important to keep your eye on the long term. An attractive payout today isn't worth much if the company might be forced to reduce or cut its dividend down the road.

On the other hand, seasoned businesses like medical devices maker Abbott Laboratories (ABT 1.12%) have a track record of paying investors for decades on end without flinching. But is that enough to make Abbott shares worth a purchase today? Let's take a look at the underlying business and decide.

Hard to find a payout with a stronger track record 

There are two crucial factors for determining whether Abbott is worth buying for its dividend income: growth and sustainability. Abbott's dividend has grown like clockwork, with a most impressive 51-year history of annual increases. As of late July, its annual dividends per share have grown by an average of 7.4% per year.

To accomplish that result, the company competes in a huge array of healthcare markets -- including the banal (like its Pedialyte hydration products) and the indispensable (like its cardiac stents and pacemakers).

In the second quarter, the company brought in $10 billion in revenue, down by about 11% from a year prior. Management attributes the decline to falling demand for its coronavirus rapid diagnostic tests, but expects that its many other segments will make up for the difference soon enough.

And there's reason to believe management is right, given that the business has successfully invested in research and development (R&D) to come up with new in-demand products for decades. Wall Street analysts see it bringing in revenue of nearly $42 billion next year while remaining solidly profitable. And over the last 10 years, its quarterly revenue rose by nearly 107% -- not very fast, but consistently in the correct direction nonetheless.

With a payout ratio of around 58% of its earnings, the stock is extremely likely to continue paying its dividend at the current pace. And as a crucial supplier to the healthcare sector, Abbott is big enough to easily weather declines in individual segments, even when those declines are sharp, as with its coronavirus tests.

In other words, Abbott Labs doesn't necessarily have a competitive advantage in any single market, but it has so many different markets to compete in that it's quite unlikely to be a loser in all of them, or even more than half. Still, it's important to note that the pace of its dividend hikes isn't very quick, so you'll need to hold your shares for a very long time to generate much in the way of passive income.

Don't get your hopes up for growth

There are a couple of catches with buying Abbott for its dividends. That includes its forward dividend yield, which at 1.8% is only a touch above the market's average.

That means if you wanted to make $1,000 in annual passive income, you would need to invest around $55,555, which is a large sum that's far more than most investors have on hand. Of course, if you're willing to invest a lot less up front and do a series of purchases over a few years, that wouldn't be an unmanageable sum to invest, but it's still a barrier. 

The second catch is that as a gargantuan global conglomerate, the company isn't capable of growing very quickly. Even when it decides to enter markets where growth is likely to be faster than its average, as with its newer continuous glucose monitors (CGMs) for diabetes management, it takes a truly colossal amount of revenue and earnings to make any kind of dent in the top or bottom lines.

But if it doesn't bother you that you'll need to invest consistently in this company over time to build up a decent base of dividend income, and if it doesn't bother you that rapid growth is probably never coming, Abbott is a decent option to buy. It's fairly resilient to risks by virtue of its size and diversification, and it shouldn't be breaking its long dividend-hiking streak anytime soon.