57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

When we’re young, there are lots of things we take for granted. Our health is one example, as we only realize how precious it is when our knees start cracking in our 20s or when we start waking up in the morning with our backs aching in our 30s.

No one is immune to bad habits; it’s just a matter of getting rid of them in time. Among Americans, the consensus is that a lack of exercise, not saving money, procrastinating, and a lack of sleep are the most common bad habits, according to a 2022 survey by YouGov.

Unfortunately, that wisdom about which habits are harmful and which are good for you may come later in life. That’s why it’s sometimes beneficial to listen to our elders about them — after all, they might be living proof that smoking that cool cigarette can be really bad for you.

In a recent thread, one netizen asked Gen Xers and Baby Boomers to share their wisdom by writing, “People who are 40+, what is a [dangerous] habit that people in their 20s think is completely harmless, but is secretly setting them up to get absolutely destroyed in a decade?” So, if you’re all about longevity, check out some real-world advice from folks who have gone through it all!

#1

Ignoring dental care.

People in their 20s can skip cleanings and think, “My teeth are fine.” Decades later, gum disease, tooth loss, and expensive dental work can become a major issue.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

#2

Marrying someone you can’t really talk to.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#3

Not wearing earplugs at concerts. I was a music photographer in my 20s and now there’s always a constant ringing in my ears and I have a hard time hearing people a lot of the time .

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#4

Snoring and undiagnosed sleep apnea.

Ruins recovery/restful sleep. Starves the brain of oxygen. Snoring ruins marriages. Host of downstream issues, all serious.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#5

Not contributing to a retirement plan.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#6

Lifting with your back instead of using your legs.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#7

Not having a good daily routine, including good sleep. Not getting enough exercise and sunlight. Giving up on things that are hard too soon.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#8

Not reading. Seriously, get into a habit of reading early. You’ll thank yourself later.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#9

Focusing on being skinny instead of being strong (especially women)!

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#10

I see some great stuff here, all true.

I’ll add – anyone who’s in their 20’s – being overweight is a problem for you to tackle NOW, not when you’re 40.

This is the ONE thing I wish I could go back in life and redo – a healthier diet, more exercise, drinking a helluva lot more water, and generally trying to stay in good shape. You don’t have to be a WWE superstar. Simple cardio, push ups, sit ups… All stuff you can do at home.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#11

Allowing $ to leak out of your bank account for convenience purchases. No matter what your income, learn to budget carefully and stop comparing yourself to others. Something as simple as eliminating any gas station purchase other than actual fuel has a meaningful financial benefit over the course of a year.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#12

I’ve noticed that smoking cigarettes is cool again amongst young Gen Z. Cmon kids! That’s crazy.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#13

I’m not 40 yet but the answer is sleeping too little and not eating enough fiber.

EDIT, since this is apparently reaching some people: I always suggest looking into what you can add flaxseed to for fiber intake (it’s also an egg substitute for some baked goods!). It has a lot of good properties. People have also been mentioned psyllium husk, oatmeal, and benefiber. (: I’ve also added edamame beans to my diet, and most places have frozen versions where they’re unshelled, so super accessible and a great snack in my opinion as someone who despises most beans and their texture.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#14

Ignoring your mental health and then realizing you don’t know how to have close relationships. I got my life figured out but some folks I knew didn’t and they’re still in the same cycles.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#15

Sugar consumption.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#16

I call it the “fall apart 40s”. Everything that you neglect in your 20s comes to bite you in your 40s, but the biggest hits that no one talks about is your mental health and your relationships.

Not learning how to make, keep and tolerate friends is damaging long term. People who keep their circles too small end up very lonely and isolated. People that don’t learn how to identify the difference between a party friend and a real friend end up with lots of people who never show up when it counts

People are more irritable in our 40s if they haven’t learnt how to let things go, and have compassion for people they don’t understand. Being intolerant is terrible for your relationships, but it also wrecks your resilience. Being intolerant becomes more stressful over time and acts like emotional plaque. It eats at you and pushes others away. Everyone is annoying and awful in some ways, but intolerant people can’t tell the difference between the mostly good and the mostly insufferable among us.

Even more damage though, is done by not understanding what makes a good romantic relationship, how much work it is, and what is realistic to expect. Divorce can ruin people emotionally and physically. Stress is a precipitous factor in a huge amount of physical illnesses and I have seen people get sick from the stress of divorce, custody battles bankruptcy etc.

Do not fall in love and get married quick. A bitter divorce starts with a whirlwind romance like 8 out of 10 times.

If you have good people with good values in your life who will actually be honest with you, make sure they like your partner.

If you were raised by selfish jerks, learn what good people are like, because you are at a super high risk of getting together with someone who treats you badly. Because someone who treats you badly in the long run will sweep you off your feet in those first few months.

Learn how to manage your thoughts and emotions and deal with the things you buried. The muscles that hold down your pain atrophy like every other muscle and by your 40s that stuff starts to surface. Go to therapy.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#17

Not having good ventilation when doing diy or art projects. .

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#18

A couple beers in the evening is gonna MESS. YOU. UP.

They cause inflammation, bloating, and greatly reduce quality of sleep.

I wish I’d have known / listened sooner, because just cutting alcohol on work nights has made my life WAY easier.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#19

It’s the “NOT” doing things.

NOT brushing your teeth
NOT walking daily
NOT maintaining flexibility through stretching
NOT getting enough protein
NOT getting enough sleep
NOT drinking enough water.

a lot of this stuff you can start doing in your 40s, but adopting those habits later will feel like “lifestyle changes”
and be much tougher to do.

stretching is so easy when you’re already stretchy. once you’re stiff and can’t reach anything, it’s harder.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#20

I’ll take this as a personal question as a 54yo guy.

For gods sake, stay away from extreme sports. Skating, mountain biking, snow boarding. My bones ache, my ankles, my knees, my back. I got this twingy thingy in my elbow that will just explode in pain for no other reason to get me to drop things.

Music…turn that down. I’m a guitar player and at one time had 2 Marshall stacks. WHAT…WHAT…what did you say?

Alcohol…avoid that. For any other reason that it destroys you. I would give anything to be able to talk to some of my friends from back in the day. Can’t, they either passed, in jail, or still messed up and will just ask for money.

Now I’ve got some great stories and had a lot fun in my life but I’m paying for it now. I wish I could exercise more but most days as a 54yo I feel 70. I just ache.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#21

Don’t be afraid to be alone.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#22

Inhaling stuff that isn’t air.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#23

Making friends with people who have toxic habits…alcoholics, gamblers

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#24

Stress.

Seriously, don’t work yourself to the bone chasing the rat race.

As soon as you can, prioritise relationships, family and mental wellbeing.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#25

Not treating headaches and thinking it’s nothing the then find the root cause in your 40s that it was undiagnosed high blood pressure and your kidneys are suffering since you were eating ibuprofen like it was candy. Then need to get on dialysis and eventually a kidney transplant. Yes this happened to me and got my wife’s kidney a few months ago and I’m only 46.

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#26

Sitting there staring at your phone when people are trying to spend time with you.

How about you stop texting and go make memories with your kids?

57 Habits People In Their 20s Think Are “Harmless” But Will Absolutely Destroy Them In Their Later Years

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#27

Never learning how to sit with
discomfort.

Every time something feels hard,
boring, or uncertain you scroll,
snack, or switch tasks.

Feels harmless at 22.

By 35 you can’t focus for 20 minutes,
can’t finish what you start, and have
no idea why your life feels scattered.

Attention is a muscle.
Most people let it atrophy completely
without ever noticing.

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#28

Stress and sun exposure.

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#29

Sitting all day.

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#30

People Pleasing.

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#31

Bad posture.

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#32

Not making friends.

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#33

Energy drinks.

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#34

Having children with their “first love.”

Don’t do it.

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#35

Tanning. Why are people still doing this?

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#36

Not saving enough money. Don’t save “what’s left”…there’s never enough left if you don’t pay your future self first.

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#37

Don’t count on any job lasting, no matter how much like a “family” they try to make it seem. If you’re around long enough there will come a time when your salary gets a second look, and at some point you will get kicked to the curb.

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#38

Consistently eating more calories than you need.

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#39

Being shy and afraid of rejection. When you are old, you look back and kick yourself for not going for it.

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#40

Outsourcing their thinking and cognitive abilities to AI.

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#41

If I could go back and give my younger self one piece of advice, it would be to stop treating junk food like pizza, fast food, and other ultra-processed foods as everyday meals. The damage doesn’t happen overnight, that’s what makes it so insidious. It builds slowly over decades, affecting your weight, heart, blood vessels, joints, metabolism, and overall health long before you realize what’s happening. When you’re young, you feel invincible. Later, you discover that your body has been keeping score all along. I’d make that change in a heartbeat.

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#42

Weak core muscles and no stretching.

Many complain of back issues when they’re older, me included. I was plenty active. Snowboarding, mountain biking, hiking and just generally being outdoors. I went to the gym and had some physical jobs in the AF.

You know what I never really concentrated on? Core strength. I’m not talking some sit-ups either. I did those. I did the twisty gym machine as well.

I’m talking actual deep core exercises. My core is a constant struggle now because I’m unable to be as active due to other issues. When I’m unable for longer stretches, my core gets weak quickly. Which causes really bad low back pain. It takes a few months of PT visits to get back on track.

I have slipped L4/5 twice. It required surgery the first time, after a month of waiting to get in for my follow up after an MRI. The 2nd time it was fixed with an hour on “the rack” every day for an entire week. Then a week of pure resting. I hated it.

Do some yoga. Do core strengthening exercises. Stretch. Back issues will knock you on your door quickly. It’s all downhill from there.

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#43

Choosing the wrong life partner. If he/she is “fine” and “fun”, that’s not enough. You’ll spend the rest of your life with them. Talk about how do you plan to raise your kids, figure out how finances will work before, during and after kids, make sure you respect them for something (hobby, job, personal trait). 

We spend more time picking out our next tv than figuring out who to spend the rest of our life with. 

Edit: And if you care about looks, make sure you like the way they look now. It will likely not get any better. Might be superficial, but important for many. .

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#44

Have a target, have a plan.

The single most important thing. It is not important how near sighted or shallow your target is. May it be to have a lamborghini before 30, may it be to be juggling 4 balls or becoming the fastest person alive anything that you have gusto, enthusiasm for , unimportant how small or insignificant, it is hundred times better than not having a target.

It does not have to be an epic or exotic or powerful thing. It does not have to be a lifelong strategic, ambitious thing It just needs to be practical… If you dont like it after sometime or if you find a better one fine you can switch, but dont you ever stay without a target, any target.

And the second one is to have a plan. Again any plan would do, just have one and start. Everything else will fall into place.

You may be thinking (regardless of age) “I’m not sure what to choose, I want to know the world better before deciding on a target. Till then I want to wander” This is perfectly fine, wandering freestyle is one of the best things to do. But do it with a target, any target.

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#45

Living pay check to pay check instead of living below your means. .

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#46

Trying to maintain a weight that is too low for you. I lost my period for 12 years and have many health consequences.

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#47

Eating late at night. Hard as hell to break.  .

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#48

Not stretching.

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#49

Vaping i don’t think people assume it’s completely harmless but i don’t think they realize the severity of the dependence myself being included id do anything to go back in time and slap the silly out of myself for even trying it

edit to add: im worried even if i quit my body will never fully recover since i started SO young its actually depressing.

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#50

Living in fear. Not believing in yourself. Missing opportunities. .

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#51

Voting for morons/not voting at all.

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#52

Avoiding opportunities (“I’ll have time later.”).

You don’t have time later. Travel. Move. Chase the dream job. Live.

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#53

Staying and living in America. Get out while you’re young and can bring value to another country. Unless you are privileged enough to have family money, college paid for, etc… GET. OUT. America is not a safe place to be amongst the working class.

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#54

Ignoring protective equipment for your eyes, lungs, ears, skin, etc. and allowing yourself to be exposed to chemicals, vibrations, etc.

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#55

Blood pressure.

High blood pressure when left unchecked will take your kidneys and your heart from you.

Currently looking for a kidney after completing cardiac rehab. Don’t mess around with it. If diet and exercise aren’t enough, go to the doctor. I’m 41.

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#56

You can still get a really nice tan using sunscreen…it literally just blocks the bad UV that damages your skin.

Regardless, anytime you’re going to be out in the sun, put some on your face.

80s kids were raised by moms who thought sunburns were a normal occurrence. They’re not.

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#57

Accepting a relationship without physical intimacy because you love the person.

If you have any kind of libido, don’t deny yourself, it’s important and will drive you insane.

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