The average holding period for a stock is less than six months. That's down from an average of more than eight years for investors in the 1950s. While a decline in trading commissions has been a big driver of shorter holding periods, most investors have developed a very short-term mindset when it comes to owning stocks. 

I try to take the Warren Buffett approach, whose favorite holding period is forever. I aim to buy stocks I intend to hold for a long time. Enbridge (ENB -1.21%) is one of them. I've held shares of the Canadian energy infrastructure behemoth for almost six years and hope to own them for the rest of my life.

Delivering a durable and growing dividend

I started my Enbridge position shortly after it acquired Spectra Energy, creating the largest energy infrastructure company on the continent. I believed the increased scale and move toward lower carbon natural gas would give the Canadian utility and pipeline giant the fuel to continue growing its attractive dividend.

That thesis has played out as expected. Enbridge has continued to increase its payout. Last year marked its 28th straight year of dividend growth. 

I've steadily added to my Enbridge position over the years, further increasing the income I collect from the energy infrastructure giant. It has grown into one of the largest contributors to my dividend income.

Built to pay a sustainable and growing dividend

I plan to continue growing my Enbridge position. The driver is the company's meaningful and steadily rising dividend. Enbridge currently yields 7.5%, a well above-average payout considering the S&P 500 yields about 1.5%. I expect its attractive dividend will continue growing in the future.

That big-time payout is on an extremely sustainable foundation. Enbridge generates very durable cash flows. The company gets 98% of its earnings from low-risk sources like long-term cost-of-service contracts or government-regulated rate structures. Meanwhile, it has diversified income sources as 50% of its earnings come from liquids pipelines, 25% from gas transmission, 22% from gas distribution, and 3% from renewable power. Enbridge has focused on moving away from liquids over the years to lower carbon energy, first with the Spectra Energy acquisition and recently with its deal to acquire three natural gas utilities from Dominion.

Enbridge pays out a relatively conservative percentage of its stable cash flow in dividends, targeting 60% to 70% per year. That gives it a big cushion, allowing it to retain cash to fund new investments. Enbridge also has a strong investment-grade balance sheet. Even after funding its utility acquisitions, Enbridge expects its leverage ratio to remain within its 4.5 to 5.0 target range while trending lower in the coming years.

The company's post-dividend free cash flow and balance sheet capacity provide several billion dollars of annual investment flexibility. That gives it the funds to support its expansion project backlog, which will grow to 24 billion Canadian dollars ($17.9 billion) following the Dominion gas utilities deals. Current capital projects include natural gas pipeline expansions, offshore wind farms in Europe, and gas utility expansions. Those investments support Enbridge's outlook that it can grow its earnings by 5% annually over the medium term. That growth should give Enbridge plenty of fuel to increase its dividend.

Enbridge also has a large pipeline of projects under development. It's working on many lower carbon energy opportunities, including carbon capture and storage, blue ammonia production and export, and additional renewable energy projects. It also has the financial capacity to continue making acquisitions as opportunities arise. These future investments could enable Enbridge to continue growing its earnings and dividends in the years to come.

A great income stock to hold for the long haul

Enbridge is growing into an important income supplier for my portfolio. I expect that will continue as I grow my Enbridge position and it keeps raising its dividend. Given the company's low-risk business model, financial strength, and increasing focus on lower carbon energy, I could hold this dividend stock forever.