21 Things People Do When They're Younger That Makes A Significant Impact On Your Life Once You Turn 40

They always say hindsight is 20/20 and it couldn't be more true. When you grow up, you learn all sorts of life lessons and continue to do so well into adulthood.

Person sits on a rock overlooking a scenic coastal view at sunset
Rbkomar / Getty Images

Reddit user Additional-You3342 asked, "What is something people in their 20s might not realize will significantly impact them as they reach their 40s?" A ton of people got real and chimed in with their thoughts. Here are some of the most impactful things they shared:

1."Life is short and your time is incredibly valuable. Spend it well."

Zach Galifianakis, Ed Helms, Justin Bartha, and Bradley Cooper toast on a rooftop with the Las Vegas strip in the background in "The Hangover"
© Warner Bros. / Courtesy Everett Collection

2."Sleep is really important and you can't get away with not sleeping for one day."

u/Bella_Asian

3."When you marry a person, you marry into their family. If they have a terrible person in their family, and they do not set boundaries with them, that's a red flag. Family is complicated, but there are lots of stories about horrible in-laws causing divorces."

Anne Hathaway in a wedding dress, holding a bouquet of bright flowers, stands beside a mirror, reflecting her image in "Bride Wars"
© 20th Century Fox / Courtesy Everett Collection

4."Skipping the work needed to sustain relationships. Friends in your 20s come easily. Friends in your 40s and up take the effort of a part-time job."

u/Snugglebutt85

5."Benefits of fitness. My father started exercising regularly in his 40s. Nothing extreme, just consistent. He is now 87 years old and still in great shape. All of his doctors agree that the reason he is in such good health is because he started exercising regularly."

A row of dumbbells on a rack in a gym. The weights are neatly arranged in increasing order from front to back
Valerii Apetroaiei / Getty Images

6."The character of the person they choose to have a long-term relationship with, or even marry. The single most important decision someone will ever make."

u/SueYouBlues

7."Laying around in the sun with no protection on."

A woman applies sunscreen to her shoulder while standing on a sandy beach with the ocean and a bright sun umbrella in the background
Javi Sanz / Getty Images

8."I think a lot of people in their 20s underestimate how important their health choices are. It's easy to think you're invincible, but those late nights, bad eating habits, and lack of exercise can catch up to you. Taking care of your body now can make a huge difference in your 40s."

u/RelevantFoot7196

9."Your hearing. Loud noise over time is bad and not fixable."

Person wearing yellow headphones, a black crop top, an open jacket, and holding a smartphone smiles while walking outdoors
Abraham Gonzalez Fernandez / Getty Images

10."How long it takes to get good at something. For example, if you want to become a good writer, you will have to spend hundreds of hours writing bad, mediocre, and decent text first. And the same applies to painting, musical instruments, or any skill. As you age and gather responsibilities, your available energy and time for such activities will generally only decrease. It is very easy to keep delaying this strenuous and sometimes painful process of getting good, and you end up without hobbies and non-career related skills in your 40s. And that might be enough for some, but it might not be for you."

u/Fimbulwinter91

11."Don't just stretch. Activate and use your muscles! That's a lot of what yoga is as well. Use them or lose them, that's how injuries happen."

Two women practice yoga in a living room
The Good Brigade / Getty Images

12."How you treat people. We are all people and deserve kindness and empathy to an extent. In your 20s, it's usually not in the forefront of your mind."

u/Mamaofthreecrazies

13."That tiny dream you have of doing that thing for a job? Go after that."

Graduates in caps and gowns celebrate by tossing their caps into the air in an outdoor graduation ceremony
Skynesher / Getty Images

14."Stop slouching. Trust me."

u/sarasan

15."More than anything, start saving as early as you can. It's not easy, and I would certainly not blame anyone for having a hard time with it early on. But the moment you start making more consistently is the moment you start saving!"

Four jars labeled Retirement, House, Vacation, and College, each filled with cash
Jgi / Getty Images / Tetra images RF

16."Emotional trauma you don't deal with literally turns into physical trauma. Stop clenching your jaw. Get that trauma out of your body. Talk to someone. Your bones will thank you for it. My father doesn't have discs between his back bones because he thought he could tough it out."

u/Shh-poster

17."Who you have children with."

Stu, Did, Tommy, and Dil from "The Rugrats" sitting in a hospital room
© Paramount / Courtesy Everett Collection

18."What I'm most surprised about as a 45-year-old is how my life, while good, has no resemblance to the plans I had for it in my 20s. "Man plans; God laughs."

u/tmroyal

19."There is a lot less life than you think. If you are living to work, you're not living at all."

Cristin Milioti and Andy Samberg lounging in the pool with floaties and drinks in "Palm Springs"
Jessica Perez / © Hulu / Courtesy Everett Collection

20."The fact that their parents helped them so much. I.e. paid for their college, gifted them their down payment for a house, or called in a favor that got them a good entry-level job."

u/palbuddy1234

21."You are not trapped in your job, career path, hobbies, interests, or friendships. You are young and able to explore and try new things relatively consequence-free. A lot of people in their 20s don't think about this concept. They go to school and work, then wake up in their 30s or 40s and think f--ck, why am I in this position? Take the time to be cognizant of the path you're on, and what is fulfilling, interesting, and important to you. Of course, being physically and mentally healthy are patterns that are good to ingrain when you're young as well, as others have mentioned. Take responsibility for finding your calling and not settling or being complacent in the first hand you're dealt."

DeWanda Wise, Gina Rodriguez, and Brittany Snow sitting at a park in the evening in "Someone Great"
Sarah Shatz / © Netflix / Courtesy Everett Collection

What's something from your 20s you didn't realize impacted you until you were older? Share your story in the comments!

Note: Some responses have been edited for length and/or clarity.