There's always something scary yet satisfying about buying shares of a company you plan to hold for as long as you can manage. Between the excitement of putting your money at stake and the expectation of getting a reliable return, everyone's portfolio could use a few steady stocks for long-term growth. 

One good way to find businesses with enduring appeal is to look at companies that are upstream of major industries. Providing key inputs to primary players can insulate companies from some of the chaos that can roil economies and markets -- and as long as the industry itself is growing, there's money probably to be made.

Let's look at two examples of this kind of relatively safe and steady stock that is ready for buying right now. 

An investor ponders a computer screen depicting economic data while sitting in an office.

Image source: Getty Images.

1. Thermo Fisher Scientific

Unless you're in healthcare or biopharma, there's a good chance you've never heard of Thermo Fisher Scientific (TMO 1.33%), but it's a giant and very consistent business that could make you richer in the long term.

The company makes all manner of products for pharmaceutical and biotech players, with its offerings ranging from basic laboratory equipment like centrifuges to molecular biology reagents and gene analyzer devices, not to mention biomanufacturing hardware like bioreactors.

It also sells clinical and research-use diagnostic tests, and helps customers with their clinical trials or manufacturing needs for a fee.

Because laboratories tend to need a regular supply of the reagents and disposable vessels that they buy from Thermo, 46% of the company's $44.9 billion in revenue for 2022 was from recurring sales of consumables, and 36% is from the services it provides, which makes its top line quite predictable.

What's more, in the last 10 years, its annual net income rose by 445.8%, nearly reaching $7 billion. There is little reason to expect its growth to slow significantly anytime soon -- as long as the biopharma sector continues to expand over time. 

Of course, there's also little reason to expect Thermo's rate of expansion to accelerate much as it's constrained by its underlying markets. Still, given that it's one of the most critical upstream suppliers to biopharma, and that it doesn't have any problems with staying profitable, if you're patient, it's a good bet.

The biggest risk is that over the next decades it'll fail to keep making new products that fit the fancy of its customers. But with $1.4 billion in research and development (R&D) expenses in 2022 and an unparalleled understanding of customers' needs thanks to its deep integration into their supply chains, that doesn't seem likely anytime soon.

2. NextEra Energy

Generating electricity cleanly is a steady trade as pretty much every industry needs plenty of power to continue growing. That's precisely how NextEra Energy (NEE 0.48%) was able to grow its annual earnings by an average of 15.1% per year since April 2003, hiking its dividends per share by an average of 9.2% each year along the way.

In 2022, the utility giant reported $20.9 billion in revenue and net income of $4.1 billion, and with the ongoing global transition toward greener energy sources, it's hard to see how those totals won't rise in the coming years. 

NextEra's steady returns for shareholders aren't based just on producing new electricity from its $159 billion in power assets, though. It's also looking to expand its energy storage capabilities, as part of the equation for delivering reliable power via renewable sources entails retaining previously generated electricity in banks of batteries for later use.

Through 2026, NextEra expects to add up to 6.8 gigawatts of battery storage capacity, not to mention as much as an additional 14.6 gigawatts of wind farm capacity and up to 19 gigawatts in new solar panel capacity. Those assets will contribute substantially to the 65 gigawatts the company currently has in operation, and they'll also ensure that it continues to have plenty of money to pay off the costs of its prior investments in building capacity. 

In the long run, the biggest risk of holding NextEra is that the regulations and public attitudes pertaining to generating energy will change. It operates several gas, oil, coal, and nuclear energy plants, all of which could face new restrictions or outright prohibition if a public backlash against dirtier energy sources gets translated into new public policies. 

But as management anticipates the most recent major legislative package -- the Inflation Reduction Act (IRA) -- to become a major tailwind for the company by lowering the costs of spinning up green energy sources, that risk looks minimal for now. So with such a long runway for growth, NextEra presents a decent buying option for most investors.