One thing that makes it scarier is feeling like you haven't accomplished all the life stuff you set out to in your teens or 20s. We're not talking about climbing Kilimanjaro (though that certainly would be cool) - we're talking about becoming the happiest, healthiest, all-around best person you can be.
To that end, we've put together a list of some the skills you'll want to master by the time your 50th birthday rolls around - as well as the ones you should have already learned by age 40. Read on and see which ones you've yet to tackle.
By this point in your life, you've probably amassed a ton of knowledge about your career. Take the opportunity to share that wisdom with someone else - whether they're younger or whether they work in another field.
It can be a formal mentorship, but doesn't necessarily have to be. Leadership experts recommend finding a peer mentor or a "leadership buddy" with whom you regularly exchange feedback and advice. That way, you both benefit from the relationship.
To err is human. But to apologise is not something that comes naturally to everyone.
According to marketing communications professional Kerry O'Malley, the steps to a successful apology at work include acting quickly, showing up in person, explaining what happened and how you're going to avoid the problem in the future, saying "I'm sorry," and making restitution.
Not only will apologising help the person who was offended forgive you; it may also help soothe your guilty conscience, Real Simple reports.
Close relationships are important for health and happiness. So is solitude. You don't always want to be in the company of other people, real or virtual.
As Cal Newport, an associate professor of computer science at Georgetown University, wrote for Business Insider, alone time allows you to "process and regulate complex emotions." Plus, it affords you the opportunity to do what Newport calls "deep work," the kind that requires deep concentration and focus.
On Reddit, Mr Mouthbreather cites "being able to detect bulls--t" as a life skill everyone should know.
Business Insider's Áine Cain and Rachel Gillett put together a list of ways to know if someone is lying to you, including: the person may share too much information, or the person covers vulnerable body parts.
These signs don't mean the person is definitely lying, but they should put you on the alert.
Maybe you've been in a relationship for years, or maybe you're just starting out with someone new. Either way, it helps to know that your romantic (and sex) life won't always be peachy keen.
According to Dr. Ruth Westheimer, better known simply as Dr. Ruth, the most common relationship problem she sees is people having unrealistic expectations.
"Hollywood and the movies tell us that the stars have to be twinkling every night," Westheimer told Business Insider. "That's not reality of life."
To be sure, Westheimer isn't advocating low expectations for relationships or sex lives. Her philosophy? It's important "to be realistic, but to still have hope."
Life is stressful - that's a given. Stress management is less about getting rid of things to worry about than it is about learning to handle those worries well.
The world's most successful people have figured this out already. For example, Bill Gates reads before bed; Warren Buffett plays the ukulele; Sheryl Sandberg simply turns off her phone at night.
Other effective ways to manage stress include focusing on what you can control and staying aware of what typically stresses you out.
This is an essential skill for any adult, AuroraLux writes on Reddit.
According to Adam Galinsky, a professor of business at the Columbia Business School, one way to get what you want is to see things from another person's perspective. "When you think about what the other person wants, they're more likely to give you what you want," Galinsky said in a TED Talk.
Another tool is asking people for advice, so they become your allies. A third tool is tapping into your passion, so you seem like an expert when you speak and so other people are more inclined to listen to you.
"You don't have to talk as soon as the other person's finished," weareallnone writes on Reddit.
It might be tempting to gush about your own experiences - and you probably have many interesting ones. But a solid life skill is learning how to be patient and let your conversation partner take the stage. In fact, that's a good trick to make people like you.
An anonymous redditor says this is an essential skill that everyone should know.
Researchers say there are different personality types in the workplace, and some are more likely to clash than others. Having an entire office take a personality test and discuss the results is one path to understanding, but there are other strategies to avoid conflict in the office.
As Business Insider previously reported, you can deal with a bossy coworker by telling the person that you're busy working on something the boss assigned you and then ignoring the person if they pop up again. And you can deal with a loud coworker simply by asking politely for the person to keep it down.
If the thought of getting into a debate with your boss over how much money you deserve makes you nauseated, you're not alone. It helps to both research and practice, as much as you can stand.
If you're negotiating your salary, the best strategy both for getting what you want and still coming off as friendly is to ask for a range including and above your target number. For example, if you're aiming for a R1.3 million ($100,000) salary, you'd suggest a R1.3 million to R1.6 million ($120,000) salary.
Another trick is to frame your proposal in terms of what you're giving the other person as opposed to what they're losing. So instead of saying, "I want R138,000 ($10,000) for my car," you'd say, "I'll give you my car for $10,000."
We know it's hard to hear, but it's helpful to wake up at the same time every day - even on weekends. If you oversleep for even a few days, experts say you risk resetting your body clock to a different cycle, so you'll start getting tired later in the day.
On a related note: Experts also advise against hitting "snooze" and going back to sleep when your alarm goes off in the morning. Instead, hit the snooze button once and use the time until your alarm goes off again to turn on a lamp and do some light stretching.
Chances are good that, if you're feeling awkward about chatting with a bunch of impressive people you've never met, other people are feeling the same way.
But as Marjorie Gubelmann, CEO of Vie Luxe, told Oprah.com: "Even if you won't know anyone and you're feeling intimidated, you must go. Do not stay home. So many people are afraid that no one will talk to them and they'll leave feeling awful - but has that ever happened to you?"
One solid way to improve your small-talk skills- and alleviate some of the pressure you feel - is simply to demonstrate interest in your conversation partner. Ask the person questions, let them talk about themselves, and allow them to teach you something.
A professor of behavioural medicine told The New York Times that research suggests people who dislike or feel inept at their workouts are unlikely to continue. So experiment and find an activity you really love, whether that's spinning, Zumba, or weightlifting.
Remember: In your 30s, you start losing muscle mass, so it's especially important to exercise at this time.
Brian Fetherstonhaugh, worldwide chief talent officer at The Ogilvy Group, writes on TIME.com: "Your career sweet spot is the intersection of three things: what you're good at, what you love to do, and what the world values."
He says you should "use your 30s to test out hypotheses," like whether you're skilled enough in one area to make a career of it.
Your golden years are inching ever closer - and you'll want to be prepared to enjoy them.
As Business Insider's Lauren Lyons Cole reported, by the time you're 40, you should have saved about three times your annual salary.
Investing your money can grow your savings exponentially - without you having to do much of anything. In fact, Lyons Cole, who is a CFP, reported that "missing out on stock market growth spurts is actually riskier than not investing at all."
On a Reddit thread about lingering regrets people have from their 30s, multiple people posted about not spending enough time with their family.
For example, mustlovecash writes that they regret "not spending more time with my parents - walking, talking, travelling - while they were still young enough to actively enjoy it" and "ever, ever choosing work time or personal time over spending time with my wife and children. Children grow quickly, and leave home quickly, and the spouse who remains with you will again become the closest and most important person in your life."
Indeed, according to the Harvard Study of Adult Development, good relationships keep us not only happy, but healthy as well. Interestingly, the study found that quality of relationships is more meaningful than quantity once you hit 30.
According to Glasrud, the best way to muster up the confidence to turn down a request is to recognise that "[t]here are some things you can never have back. Your time, your health, your virtue, your life.
"Don't mess around with those things. It's fine for people to ask - most likely, in their mind, they're trying to help introduce you to a great person or opportunity or meaningful cause. And it's just as fine for you to say 'no.'"
In some cases, you can even say "no" to your boss- sort of. According to national workplace expert Lynn Taylor, if your boss presents you with a new assignment and you're already overloaded, you might respond with:
"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?"
If you're looking to start de-cluttering, there's a whole movement to support you, inspired by Marie Kondo's "The Life-Changing Magic of Tidying Up." The process starts with a tidying "marathon," in which you keep only those items that "spark joy" - and get rid of everything else.
As Business Insider's Erin Brodwin reported, clutter can be a source of stress for some individuals and families. Then again, people tend to be more creative in messy environments - so if you aren't feeling motivated to re-organise your entire office space this second, that's probably okay, too.
Writing on Quora, Vishwa Sharan advises 30-somethings to develop hobbies. People "forget that there is a beautiful life outside of their work," Sharan says, and it's important to find non-work activities you can pursue for the rest of your life.
If you're looking for ideas, Business Insider's Rachel Gillett put together a list of 15 hobbies successful people practice in their spare time, from bridge (Bill Gates) to playing the ukulele (Warren Buffett).
In case you haven't heard, it's not so easy to find BFFs once you're off a college campus. That doesn't mean it's impossible - in fact, there are plenty of science-backed strategies for forging friendships in adulthood.
One way is simply to do activities you enjoy so that you meet a steady stream of people with similar interests. Another way is to make yourself a little bit vulnerable: Exchanging confidences as a relationship progresses can make two people feel closer.
As the late psychoanalyst Hedda Bolgar told Oprah.com when she was 103 years old and still practising: "It's important to be part of a community!"
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