I turned the big 5-0 this summer, and I realize that 50 doesn't seem as old as it did when I was half my age. I'm still excited about my future prospects, and that also means that I'm even more passionate about investing than I was in my youth. 

I'm just a few weeks into my 50s, but I think I have a decent grasp of stocks that I wouldn't mind owning for the next decade or two before I shuffle off into retirement. I'm also going to single out companies that I think may be relevant to 50-somethings like me.

Kevin Spacey saluting in "House of Cards" on Netflix.

Image source: Netflix.

Planet Fitness

You're only as old as you feel, and staying in shape is a good way to lead an active life well into your golden years. Gyms are a good place to work out, but traditional fitness centers full of young hardbodies and even stiffer monthly fees can be demoralizing to your psyche and your pocketbook. Planet Fitness (PLNT 0.05%) has emerged as the value-minded gym for the masses. 

Planet Fitness operates a growing chain of gyms with monthly rates starting at just $10 a month and peaking at $20 a month. It's easy to get started, and anyone that's ever been tethered to one of those $60-a-month uber gyms will be happy to know that it's just as easy to bow out. It's free of frills, sticking to a wide arsenal of workout machines. The model works. Planet Fitness posted another quarter of rock-solid results on Wednesday. Revenue climbed 17% with adjusted earnings growing even faster. Comparable-store sales rose 9%, and it's not a fluke. Comps have risen for 42 consecutive quarters. 

Netflix

They say that millennials are responsible for the cord-cutter movement, but one can argue that it's also more seasoned video buffs who prefer to view content on their terms. Who wants to wait a week for the next installment of a show? Who has time to sit through long commercial breaks?

Netflix's (NFLX -9.09%) growing catalog of streaming content is unmatched, something that only Netflix can do as it reaches 104 million subscribers worldwide. Netflix has emerged as an undisputed market darling. It was the S&P 500's top gainer in 2013 and 2015, and it's one of the biggest winners in 2017, up 42% year to date.

No matter what your interests are, there's a good chance that Netflix's vault has more than enough content to make you forget about the cable or satellite television plan that you used to overpay for. Netflix wins.   

Camping World Holdings

Folks are retiring with health on their side, something that wasn't the case in previous generations, and that's why I'm going to make Camping World (CWH 1.18%) my third recommendation for folks in their 50s.

Camping World operates the largest chain of RV showrooms with 126 superstores as of the end of March. The company does it all. It sells new RVs. It buys and resells used units. It also services the vehicles and offers outdoor living accessories. It operates the Good Sam Club, the RV world's equivalent of AAA. Camping World's been growing by acquiring regional players that it can transform with its brand, a smart move to scale quickly in this highly fragmented sector. 

Camping World reports quarterly results after Thursday's market close, so there's always a chance that this stock makes a big move up or down on Friday. That's OK. We're in our 50s now. We have miles to go before we sleep.