It's easy to get distracted by short-term market trends -- even if you're a seasoned investor. But avoiding emotional decisions and the temptation to try to time the market is vital for your long-term portfolio goals. 

Instead, consistently putting money to work in the stock market, whether it's up or down, and diversifying increases the likelihood of success over time. If you're looking for remarkable stocks to add to your portfolio this month that you can hold for years, here are two names to consider right now. 

1. DexCom 

DexCom (DXCM 1.76%) has a leadership position in the diabetes care space thanks to its continuous glucose monitoring (CGM) devices, which track patients' glucose levels.

In 2022, the CGM market hit a valuation of about $7.8 billion. DexCom generated about 40% of that amount with its top line totaling just shy of $3 billion, up 20% from 2021. That was driven by 16% growth in U.S. revenue and a 28% surge in international revenue from 2021.

Profits for the year hit $341 million, a 57% jump from 2021. A number of factors drove DexCom's continued growth, even amid increased competition in the diabetes care space. For one, the number of patients is expanding. CGMs are used by both Type 1 and Type 2 diabetics, and there are even potential use cases for pre-diabetics.

Each of these markets remains significantly underpenetrated. Case in point: Only about 4% of Type 2 diabetics in the U.S. use a CGM device even though that is the most commonly diagnosed form of the disease.

Another notable factor behind DexCom's continued growth is the extent of the reimbursed coverage for its devices. It was recently announced that its latest CGM device, the G7, would be covered by Medicare for all eligible beneficiaries upon its U.S. launch (which is ongoing at the time of this writing).

And in the company's 2022 earnings call, CEO Kevin Sayer talked about coverage in key international markets, saying, "A great example is in the U.K., where DexCom One was added to the national formulary for all people with intensively managed diabetes."

With about 1.7 million people around the world using DexCom's devices as of the end of 2022 (a mere fraction of the roughly 422 million people globally with the disease), the company has both a strong market foothold and a rapidly growing base of patients to tap into from here.

For long-term healthcare investors, DexCom could make a compelling investment opportunity in any market environment.  

2. Airbnb 

Airbnb (ABNB 1.15%) dealt with a nearly impossible market environment at the start of the pandemic, but has roared back to growth and hit record profits. The return of cross-border travel and leisure travel has certainly been a factor, but these elements are far from the only catalysts. 

In the final quarter of 2022, Airbnb witnessed its highest level of active bookers ever. The company closed out the quarter and year with booked nights and experiences totaling 88 million and 394 million, respectively. These figures represented respective increases of 16% and 20% on a three-year basis.

Many consumers are looking for more ways to make money in a tight economy, and hosting on Airbnb appears to be an increasingly attractive option for many. The platform ended the year with 6.6 million active listings, its highest amount ever and up 16% from the year-ago period.

In short: Demand remains high from both hosts and guests, and significantly elevated from pre-pandemic levels -- arguably a more accurate assessment of its growth story than year-over-year comparisons to the early post-pandemic travel boom.  

To illustrate the company's evolving travel base, people aren't just using the platform for short-term stays. In fact, 21% of all bookings on the platform are for stays of 28 days or more, compared to just around 13% to 16% in 2019, before the pandemic.

Airbnb's focus on upgrading its platform experience for both hosts and guests, and the diversity of the stay offerings its platform features, have created a business that caters to both the supply and demand sides of the rapidly evolving travel industry. Investors might want to consider even a modest position in this stock in the near future.