17 things to start doing in your 20s so you don't live in regret in your 40s

Hstrygeek1 has another solid piece of advice:

"Build upon friendships. There is more to life than going out every night. Stay at home with close friends. Go on adventures together.

"That being said, don't be afraid to end some friendships. Fair weather friends are not worth your time. Stay loyal to those that truly matter and invest your time with them."

Vanessa Van Edwards, a human-behavior researcher, recommends ditching your "ambivalent friends" — such as jealous, undermining, and unsure frenemies — to minimize stress in your life.

Redditor Keetlady says: "Don't get caught up in the cycle of buying expensive things to keep up with the Joneses and impress people. People in their twenties seem to want it all NOW. Don't fall into that trap."

Author Thomas C. Corley, who spent five years interviewing rich people including self-made millionaires, found that lifestyle creep — the act of spending more as you get it, to save face among or to impress your peers — erodes wealth quickly. Delaying gratification, instead, and saving that money for later has the potential to make you extremely wealthy down the line.

Redditor DrewsephVladimir has some regrets of his own:

"I wish I had taken better care of myself. Instead, I let my weight catch back up with me, I ignored a few dental problems, and I didn't take care of my finances as well as I should have.

"I mean, don't get me wrong, I'm 31 now, and none of these problems are dire for me, but God they're a much bigger pain in the ass to deal with now, compared to how much effort it would have taken to not let them become an issue at all."

It generally is easier to manage your weight when you're younger because we tend to be less active as we age, Business Insider's Erin Brodwin reports. Moreover, we may become less attuned to our bodies' nutritional needs as we get older.

Redditor rubyfisch focuses on relationships: "Do not spend one more minute of your life with someone who makes you feel like you are less than you are ... he or she will never change for the better and you might just change for the worse."

Redditor Romination says:

"This is perhaps not the advice you're looking for but maybe you should also try to avoid thinking of your 30s as some kind of stopping point for fun things, where all you can do is look back and sigh about what could have been.

"I know of several people whose 30s have been more fun than their 20s, and it's in part because they can look back with experience and realize they're better at balancing and enjoying the things they want to do. You still have so much in life, don't just let it be over because you survived another 365 days!"

Redditor Rohri_Calhoun says: "Don't burn your bridges. Personal, work, whatever. There will be times when you will need to be amiable with people from the past for various reasons and the last thing you need is someone saying 'F--- that guy' because of something petty or stupid that could have easily been avoided."

This advice applies especially when you're quitting your job.

According to national workplace expert Lynn Taylor, if your new position is in the same industry or city, there's a good chance you'll run into your former boss and coworkers again. Or, your former boss may talk to your new boss about you if they know each other. Keep it classy.

Redditor zoidbert writes about an all-too-common mistake:

"I regret not saving more money and, more importantly, I regret racking up debt. That nearly killed me in my 30s. Some of it was necessary, of course, but a lot was credit card overkill.

"I also regret not traveling more. Once we married and started having kids, travel got curtailed. We still went on trips but they were family trips. I wish I would have taken her on a couple of big out-of-country excursions before family came into play.

If you find yourself in a similar situation, consider taking a tip from one former Business Insider reporter and going on a cash-only diet, during which you stop using credit and debit cards completely.

Redditor turkoosi_aurinko has some advice for anyone who's already feeling stuck:

"Yeah, you went to high school, then maybe did some college, tech school, training or whatever and thought that was your direction. But if you finally get a job, and you're not happy, work to change that s--- immediately. Spending your entire work week being unhappy just because it pays the bills will not make you happy.

"The longer you wait to change, the harder it will feel to change. So get used to change, because you'll probably need to do it a number of times throughout your life and career."

Career coach and former Googler Jenny Blake, author of the book "Pivot," says making a career change doesn't have to be terrifying. You just need to go about the transition carefully — first drawing on your current experience, then networking, and then testing, until you're ready to launch.

"Don't compare yourself to others," writes Redditor hstrygeek1. "In the social media age, it is tempting to beat yourself up if your friends are getting married, having kids, and living a life of luxury. We each live our own lives. The only thing you're going to do is hurt yourself.

Indeed, research suggests that comparing yourself to others is pretty pointless. That's because, from the outside, people can seem a lot happier and less troubled than they really are.

Redditor techniforus writes:

"Forgive yourself. Kicking yourself over past failures won't change what happened, it will just leave you sore from being kicked so much. Give up all hope for a better past. Own who you have been so it doesn't own you.

"This really applies to all ages, but it's a skill that takes a while to develop so you might as well start young and really figure it out. I haven't met many people under twenty who have taken it to heart but I have found a number of people in their twenties who are really starting to get it. I've also met people in their 80's and 90's who still don't get it and are filled with regrets."

Journalist Kathryn Schulz says something similar: She suggests that we can expect to have some regrets, and shouldn't feel bad about having them.

"The point isn't to live without any regrets, the point is to not hate ourselves for having them," she says in her TED Talk. "We need to learn to love the flawed, imperfect things that we create, and to forgive ourselves for creating them. Regret doesn't remind us that we did badly — it reminds us that we know we can do better."

Quora user Nupur Jain includes this tip in her response.

Learning to negotiate early in your career is a pretty big deal. As Business Insider's Tanza Loudenback and Skye Gould reported, "Negotiating your starting salary — and continuing to negotiate every few years or when you start a new job — could make a $1 million difference in your lifetime earnings."

$1 million!

If you're worried about botching your first salary negotiation, make sure to do your research so you get a sense of the standard salary for your position. And remember that salary isn't the only thing you can negotiate — you can also ask about things like performance bonuses, equity options, health insurance premiums, 401(k) matches, and help relocating for the job.

That's a tip from Quora user Piyush Jbd, who writes about thinking of your weaknesses as a "competitive advantage."

It's something both Michael Phelps and Winston Churchill learned to do, as Eric Barker writes in "Barking Up the Wrong Tree."

For Phelps, having a somewhat awkward body type made him a pretty bad runner and dancer — but it also made him an incredible swimmer. For Churchill, being paranoid meant that he was once "deemed unsuitable for the highest offices" — but it also meant he recognized Hitler as a threat to the world.

Figure out what makes you weird, and turn it into the thing that makes you a winner.

This one goes back to the fear of failure. Quora user Jordan Allen says:

"Some people get the chance to see if their band could make it big or their business could skyrocket or their love of their life was moving to the other side of the world and wanted them to join. It's scary to think about the life we know versus the one we don't, and so often people drop these chances for no better reason than that they're scared."

If you think of your life as an engineering problem, you always want to be prototyping — building a model and testing it. As Bernard Roth, Stanford professor and author of "The Achievement Habit," says, you don't want to be tinkering forever, until you've got the seemingly perfect model.

So try out life in another country, or launch your business on a small scale and see how it goes. If it doesn't work out, you can always try again.

Quora user Pranav Park writes:

"This is possibly the best time to take multiple leap of faiths and learn your lessons the hard way. If you succeed, you succeed. If you fail, you have a great story to tell in your 40s. At this age, you will have all the energy, courage and spirit required to rise back. Moreover, you will not be afraid to fail which apparently sets apart successful people from the others."

Similarly, Redditor Bhruic says:

"Don't talk yourself out of doing things you want to do. Don't let fear win. If you want to vacation in Europe, do it. If you want to talk to that hot girl/guy at the bar, do it. If you want to start your own business, do it (and do the research first). Getting to your 30s and having a string of regrets is going to haunt you."

Park is right about successful people not being afraid to fail some, and therefore being more willing to take risks. Amazon CEO Jeff Bezos, for example, is notorious for this quality. Bezos has said: "Given a ten percent chance of a 100 times payoff, you should take that bet every time."

That's another tip from Rashinkar.

It's best to learn this skill now, while it's still relatively early in your career. That way, you can prioritize the people and experiences that are truly meaningful to you.

If you're looking for tips on turning down an invitation — without seeming antisocial — etiquette and civility expert Rosalinda Oropeza Randall recommends keeping it simple: "It sounds great, but I think I'll pass this time."

You can even push back on your boss when they give you an assignment you feel like you can't take on. For example, if you're already overloaded with other projects, national workplace expert Lynn Taylor suggests responding:

"I would be happy to do that project, but what that could mean is that [whatever other project you're working on] will have to be put off until tomorrow, because I was actually going to spend the next three hours finishing that proposal. Would you like me to put that off?"

So says Quora user Ruchi Rashinkar.

In other words, show some self-compassion. Scientists say it can make you more successful because you're learning from your missteps, instead of just berating yourself for them.

One self-compassion exercise involves treating yourself as you would treat a friend or a colleague who has failed. You might say to yourself: "This is really hard right now," or, "I'm sorry you are struggling."