But getting a head start, and anticipating what may trip you up, helps in getting prepared for the inevitable financial setbacks.
The goal is to be prepared enough that when decisions arise, you're not taken by surprise. Should you buy a used or new car? Should you move out or ask for a rent reduction? Should you even sign up for the 401(k) at the stupid job where you're not going to stay long? (Yes, you should.)
Here are some clues to where your head should — and shouldn't — be at during each stage of life.
Ages 18 to 22: Just starting out
Never, ever budgeting
Yup, sitting down with an Excel spreadsheet can be a drag, but avoiding planning and budgeting is the biggest mistake you can make starting out.
Flying blind makes you vulnerable to debt and bad credit.
But it's not just about staying on top of bills or avoiding a hit to your credit score: It's about building habits that will help you as you age — when setting aside cash for an emergency fund and retirement account will grow crucial.
As soon as you have your own money coming in and going out, you need to keep track of it.
Baby steps: Start with a big-picture checkup once a month and go from there.
Taking on monster levels of student debt
Have you taken out a bigger loan than you really need? Companies issuing loans certainly like to rope you into borrowing as much money as possible — and it can be confusing to know how much you is the right amount if you're new to the process.
That's bad because the debt you have at age 22 can hurt you through age 62 — and beyond.
People who put 10% or more of their income toward paying off debt after college — under a typical 10-year repayment plan — are considered to be excessively burdened by debt, according to Mark Kantrowitz, a student financial aid policy expert, who has testified before Congress on the matter.
As the amount borrowed for college has risen, so too has the proportion of students borrowing, according to Kantrowitz's study on student loan debt.
So do the math: If you're still in college, now is the time to re-evaluate how much you've borrowed and whether you can avoid taking out more loans by applying for grants or picking up cash through a side job.
Ages 22 to 26: Adulting like an adult
Being late on student loan payments.
That is not just slap-on-the-wrist late — that is shows-up-on-your-credit-report late.
The consequences of bad credit? Think paying more for credit cards, car loans, mortgages, and more.
Not maximizing your 401(k) match
One of the biggest mistakes people make in this age range is not taking advantage of the "free money" offered by companies in the form of a 401(k) match — when employers match your contributions to your workplace retirement account.
Even if it is your first job and even if you don't expect to stay long, sign up for that money now.
But if you play your cards right, you might even end up with enough to retire early — or at least at a younger age than you expect.
Tuning out at the mention of the word "investing"
Studies show that compared to other age cohorts, people in their 20s are more likely to believe investing is risky — and twenty-somethings therefore hold more in cash and less in stocks at the exact moment in life when they should take on risk, reports the Wall Street Journal.
Investing in your retirement account, and even growing your side cash in an online brokerage account, is easier than you think — and a smart way to start building wealth. Expert tip: Learn all about diversification.
Ages 26 to 30: Sh*t is getting real
Taking on a lax attitude about health insurance
By this age, you're off your parents' health insurance. That means you need to start paying attention to the nitty-gritty of what it means to be an insured adult: the differences between co-pays and co-insurance, FSAs and HSAs and more.
What may have worked for you in college or in your early 20s may feel different now that it's coming out of your paycheck.
You can't neglect the health care hunt: the time spent learning how much insurance really costs, how to fight insurance companies that overcharge you — and win, how to comparison shop for affordable care, and how to choose enough coverage.
Skipping these steps is dangerous, not only for your pocketbook, but for your health, too.
Spending like a baller
Unless you are literally making money off your Insta account, it's likely all that time spent on the 'Gram will actually make you poorer. Two-thirds of millennials say social media makes them compare their lifestyles — and spending — to those of their peers, according to one survey.
But it's a mistake to spend like the sun will shine every day, when you should be counting on rain.
Skipping the rainy day fund
Not to be too depressing, but bad things can happen and totally derail you at this stage, when people tend to be living off a narrow financial margin.
Neglecting an emergency fund is one of the biggest mistakes you can make at this point in life. You could have a medical emergency, a job loss, or even a relationship disaster that will require you to move quickly and decisively — and you'll need the resources to do it. Be prepared for it.
Ages 30 to 35: Responsibility-o'clock
Overspending on a car or home or wedding
Once you get into the get-paid-and-pay-bills groove, it can be tempting to expand your horizons on new digs, a new car, or other big stuff you previously couldn't have afforded.
One of the biggest mistakes at this time of life is overspending in a new category: buying too much car or too much engagement ring, buying a property when renting may be better — or going nuts on a wedding.
Nix those terrarium centerpieces, and start saving for the baby instead.
Avoiding "the talk"
No, not that talk.
You may be looking to get married, but before you do: Be sure you know how to talk about money, in a way that avoids fights, with your sweets. Find a good time to hash it out and talk it through.
Couples on the other side can tell you that not talking about money — your debts, expenses, how much you expect to earn, the ways you'd like to spend it — before getting hitched can be very problematic.
Thinking it's too late to start saving
Despair is your enemy: Not socking away every extra dollar and compounding that money is another one of the biggest mistakes you could make right now.
According to a Wells Fargo study, 41% of people 22 to 35 years old haven't even started saving for retirement.
That's bad because the sooner you get money into a savings vehicle, the faster it can grow exponentially.