10 important money lessons you should learn by 18—and can use forever

Financial literacy is a lifelong journey. 

Some people are lucky enough to grow up with parents or teachers who can help them understand concepts like saving and investing from a young age. But given that over 1 in 3 U.S. adults aren't considered "financially literate," according to a 2022 Ipsos poll, it's clear plenty of people aren't getting those lessons early on — if ever.

That's part of why I recently joined CNBC's senior economics reporter Steve Liesman, and deputy personal finance editor Kelli Grant, to speak with over 1,000 high school seniors in Queens, New York.

We shared our experience and expertise to help the students get a foundational understanding of how money works. These are the 10 most important financial lessons we think high school students need to know before they graduate.

1. Identify your goals, values, and desires—apart from your friends and social media

Personal finance is personal. Before you can even begin to set a budget and work toward your goals, you need to establish what those goals are. They need to matter to you.

Buying a home, for example, is a very common financial goal both because of its practicality and its potential to be a lucrative investment. But if you'd rather spend a lot of time traveling or living in different places, being a homeowner might not be your dream. 

Don't feel pressured to work toward a certain milestone that doesn't align with what you want out of life.

2. Compound interest is your best friend, so start investing now

When it comes to investing, the time your money is in the market is often as important as the amount of money you're contributing. That's because of compound interest: The cash you invest earns interest, which gets added to your initial investment and you start earning interest on the interest.

Investing pros like Warren Buffett agree: Compound interest is one of the easiest ways to build wealth, and the way to maximize it is to keep your money invested as long as you can. That's why it pays to start investing as soon as possible.

3. Be intentional with your money

Most everyone has to figure out how to live on a certain amount of money. Even if you have a lot to work with, it's very easy to go broke, or wind up in the red, if you're not keeping track. Consider how many lottery winners or professional athletes wind up back at zero.

Impulse buys are designed to be tempting. Take your time when shopping to consider if what you're tapping your card for is truly how you want to spend your money.

Understanding wants versus needs means being able to identify the things you have to spend your money on, like housing, food and bills, versus the things you want to spend your money on, like trips or concerts.

Writing down everything you spend money on in a month is a good place to start to identify where your cash is going. From there you can see exactly how much you actually have leftover after your needs are met. Then you can decide what to do with the rest, or look for areas where you can pull back on spending to meet a certain goal.

4. Talk to everyone about money: The more you talk, the more comfortable you get

In the past, it was often frowned upon to talk about money. But that attitude has allowed financial problems like wage inequality and lack of knowledge to persist.

Talking about money with your trusted elders or more experienced peers can help you learn concepts like how to use a credit card wisely or the risks of investing.

The more comfortable you are talking about money in no-stakes situations, the easier it will be for you to bring it up when it matters, like when you're negotiating a salary or putting an offer on a home.

5. Learn how to negotiate

The sooner you master the art of negotiating, the better off you'll be. When it comes to both money coming in, like your salary, and money going out, like your rent, you could be putting yourself in a better position simply by asking for a better deal.

It can be intimidating to negotiate your first job offer, but you won't know what you're capable of getting unless you ask. If your employer won't offer a higher wage, ask for other benefits like time off or a signing bonus.

Similarly, when you go to rent an apartment, you can always ask for a lower monthly price or to have utilities included in your rent. Most of the time, the worst that can happen is you're told "no." 

6. Advocate for yourself, and if you don't understand something, ask

You'll get better with money the sooner you get comfortable asking questions about it. 

If your paycheck seems lower than you thought it would be, it might be wise to consult your human resources department to make sure your tax withholdings are correct. Maybe your bank or your doctor charged you a fee you don't understand — call and ask what's going on.

You can't improve your current situation if you don't understand why you're in it in the first place. 

7. Learn from your mistakes

Everyone makes mistakes. It's all part of the learning process, so long as you actually learn from them.

Ask yourself why the error happened and if it was possible you could have prevented it. Then take that knowledge with you into the future so you don't make the same mistake twice. 

8. Surround yourself with people who support your money goals

If you're trying to save up for a spring break trip but your friends want you to go out to dinner and drinks every weekend and go shopping for new clothes every month, it may get difficult to stick to your goals.

You don't have to all be in the same financial situation, but friends who pressure you to spend money you don't have or want to spend can end up costing you big time.

On the flip side, if you have people in your life who will encourage you to stick with your goals and hold you accountable, it can feel a lot easier to succeed. 

9. Find free or low-cost hobbies and activities you enjoy

Especially while you're learning how to manage your money and beginning to build wealth, it's a good idea to find free or low-cost activities that you like, such as spending time outdoors in nature, volunteering at local nonprofits, writing, sports or making art. 

That way, you can have fun, and still hang out with likeminded people, when money is tight, or you're just trying to save for the future.

10. True wealth is about more than money

The people who feel the wealthiest aren't necessarily the people who have the biggest salaries.

Financial experts and wealthy people alike tend to agree: If you can get yourself in a position where you're not worried about money because you have some wiggle room to do things that bring you joy, you're likely to be happy and feel fulfilled. 

That is easier said than done, especially when the cost of living keeps growing. But the point is that it's possible at a wide range of income levels if you have the knowledge and skills to effectively manage your money.

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