Trading in and out of stocks may seem like the norm these days, but holding on to shares of high-quality companies for the long haul has always been, and will always be, a superior strategy. Fighting the urge to sell can be difficult, particularly when bad news sends a stock tumbling. But your future self will thank you.

Not all stocks are suitable to be held indefinitely, and sorting out the mediocre businesses from the truly great ones isn't easy. Thankfully, a few of our Foolish contributors have identified three stocks that fit the mold.

Daniel Miller: This pick is going to raise a few eyebrows, but one stock I never plan to sell -- though I hate to make such commitments -- is General Motors (NYSE:GM). I know, I know, there's a lot to dislike about the company's reputation. Like the fact that it went through a unique bankruptcy, to put it lightly, and had a disastrous and tragic ignition recall saga in 2014. If you can put those things aside, however, it seems like General Motors is finally on the right track and despite it being in a highly competitive and cyclical industry, it appears poised for long-term success.

Image source: General Motors.

For instance, GM's operations are much improved as the company continues to consolidate its number of vehicle platforms, reduce its number of plants and increase the volume per, reduce tooling cost and extend the lifecycle of its vehicle platforms. During the fourth quarter, GM said it's on track to achieve around $5.5 billion of efficiencies by 2018 that will offset brand and technology investments.

That's helped the company drive its return on invested capital to 27% in the fourth-quarter while maintaining a $20 billion cash target and returning roughly $6 billion to shareholders last year. Sales of SUVs and trucks are expected to remain red hot which will continue fueling its earnings per share, but the most recent reason GM has become a stock I won't sell is its understanding that disruption in the industry is real, and it's a really big opportunity.

Thanks to the seemingly overnight appearance of Uber, and companies like it, GM realizes there are many more technology and mobile opportunities for its business to take advantage of. GM made a recent strategic alliance with Lyft and purchased certain assets from Sidecar. GM continues to test personal mobility projects in New York City, among other places, and has grouped a number of smart mobility projects under a brand named MAVEN.

Nobody knows if GM will be able to create the next big mobility success, much like Uber has become, but GM is clearly no longer the awfully managed and poorly executing automaker it was a decade ago. Many people refuse to see that, or have yet to realize it, but I'll definitely wait to see how this story plays out.

Brian Feroldi: One stock that I plan on holding on to for the ultra-long term is Proto Labs (NYSE:PRLB), a company that specializes in rapid prototyping and custom manufacturing.

What sets Proto Labs apart from other manufacturers is that it has developed custom software that automates the design, quoting, and manufacture process, which greatly speeds up the prototyping process. Proto Labs' customers can have a real part in their hands in as little as one day, far faster than traditional manufacturers that often require weeks of lead time. That extreme speed is highly valued by product developers around the world, who are under pressure to bring their finished products to market quickly.

Image Source: Proto Labs.

Proto Labs recent results confirm that its offerings are being embraced by its customers. The number of unique developers that used the company's platform last quarter increased by 22% when compared with the previous year. Better yet, average spending per developer jumped by 3%, which indicates that once a developer gets comfortable with using Proto Labs' services, it continues to come back for more.

What's really exciting about Proto Labs' story is that the company already has a worldwide footprint. It has operations up and running in the U.S., Europe, and Japan, and it's growing by double-digit rates in all three of these geographies. 

Over time, the company has plans to layer on new services and materials to its product suite, which should help to ensure that more and more developers will use its services in the years ahead. That should give investors years of profitable growth to look forward to, which is why this is one stock I plan on never selling.

Tim Green: I won't commit to never selling International Business Machines (NYSE:IBM), as things could certainly go wrong for the company, but I do plan to hold on to the stock for the foreseeable future. IBM is in the process of transforming itself, shifting toward high-value, high-growth areas like cognitive computing, business analytics, and the cloud. The company's results have been lackluster as of late; even adjusting for currency and divested businesses, revenue is declining. But the strategy is sound, and I think that it's more likely than not that the company ultimately succeeds.

Image source: IBM.

There's been tangible progress at IBM, despite all of the pessimism that seems to be surrounding the company. Strategic imperatives, which are IBM's growth business, now account for 35% of revenue, and they grew by 26% in 2015 adjusted for currency. Total cloud revenue reached $10.2 billion in 2015, including hardware, software, and services, while cloud delivered as a service reached an annual run rate of $5.3 billion. Business analytics revenue grew by 16% to $17.9 billion, and mobile revenue, buoyed by IBM's partnership with Apple, more than tripled,

While investors wait for IBM to right the ship, a hearty dividend compensates them for their patience. IBM's dividend currently yields 3.7%, and with 20 consecutive years of dividend increases under its belt, it's likely that the company will again raise the dividend next month. While it's easy to be pessimistic about IBM's future, given the company's results, I think it's worth holding on for the long haul.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.