1. Save and invest for the long term
"Always ask yourself if you're buying something: Do I really need this? Is this something I have to have? Most of the time the answer is no. So don't buy it," O'Leary suggests. "Instead, invest the money so you can get to that equilibrium a lot sooner."
Watching your spending can help you avoid credit card debt, which charges notoriously high interest. And, by using that saved money to invest early, you can take advantage of the magic of compounding, and see your money grow while you sleep.
2. Think carefully about a mortgage
Not all debt is the same. A mortgage, for example, can be leveraged into an appreciating asset, like a house.
"Mortgages are more of a grey area than credit card debt, because real estate can be an investment," O'Leary says.
Still, paying off mortgage debt can have benefits. Self-made millionaire and wealth management expert David Bach says paying off your mortgage early can be a key for successful retirement.
"I can tell you, having been a financial advisor at Morgan Stanley, my clients who retired at 50 years old, the secret was: They had paid their mortgage off early," Bach tells CNBC Make It. With a 30-year mortgage, make a plan to pay it off in 20, or preferably 15 years, he says. To do that, contribute an extra 20 percent to your monthly mortgage payment, even if it means sacrificing elsewhere in your budget.
Unlike Bach, who says "buying a home is the escalator to wealth in America," O'Leary suggests seriously considering whether or not you should purchase a home in the first place.
"In my opinion, most people in their 20s, or even 30s, have no reason to be taking on that kind of debt," O'Leary says. "Homes don't always gain as much value as you expect — at least not anymore and at least not quickly."
If you do decide to take out a mortgage to own your home, O'Leary agrees that you should pay it off as quickly as possible.
"There's never an incentive to stay in debt. Life is unpredictable," he says. "What happens if you're laid off or incur unexpected expenses elsewhere? Your once-manageable mortgage is suddenly going to seem not so manageable."
3. Make a monthly strategy to pay off debt
If you already are in debt, commit to a method for paying it off.
Some experts recommend a strategy called the snowball method, which was popularized by "The Total Money Makeover" author Dave Ramsey.
First, write out all of your debts from smallest to largest. Focus on the smallest debt, and funnel as much cash as you can toward that debt to pay it off (while paying the minimum balance on the others.) Then, once the smallest debt is repaid, move on to the second-smallest debt. This strategy's benefit is the motivation of seeing debts disappear one at a time.
Other experts recommend the avalanche method: Start by listing out the interest rates on your debt and focus on paying off the debt with the highest interest rate. This strategy can help you save by minimizing how much you spend in interest payments over time.
4. Don't neglect your 401(k)
If you have a 401(k) retirement plan through your employer, be sure to ask if that employerhas any matching offers. If they do, that means the company is willing to match contributions you make to the account up to a certain amount.
"The company match is literally free money," personal finance author Ramit Sethi writes in, "I Will Teach You To Be Rich."
But one in five people don't contribute enough to get the match, according to data from benefits administrator Alight Solutions. Certified financial planner Eric Roberge says missing out on that opportunity is the biggest mistake Americans are making in saving for retirement.
—Video by Zack Guzman
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