This is the No. 1 money habit of early retirees, says CFP—and it only takes 30 minutes

As soon as you hear about the FIRE movement, it's hard to deny the appeal. Short for financial independence, retire early, FIRE adherents aim to save and invest large portions of their income early in their careers in order to have enough money to retire decades before their mid-60s.   

However, getting there takes some strategizing, and there's no one way to do it. Some early retirees start their own businesses and sell at a huge profit. Others aggressively buy up rental properties, effectively replacing their salary with income from their tenants. Others are able to bank upward of 50% of their salary through extreme frugality.

Rachael Camp, a certified financial planner and owner of Camp Wealth, says her clients aiming for financial independence all have one thing in common: They track where every dollar they make goes each month.

"This is a huge, huge priority for them," she says. "They typically have monthly reviews of their finances where they go through and look at their spending."

Here's why Camp says taking regular dives into your finances is essential if you want to increase your savings rate — whether you're planning to retire early or not.

Track your spending to stay on top of it

While Camp and other CFPs recommend saving 15% to 20% of your pre-tax income to put toward financial goals, such as paying down debt, building an emergency fund and investing for retirement, many FIRE adherents supercharge that rate by upping their income and keeping their fixed costs low.

No matter your goal, you're unlikely to get your savings rate where you want it without checking in, either by yourself or with the help of a pro, on a monthly basis, says Camp.

"I see this as a huge difference between people who are saving 20% or more versus people who are spending more than they're taking home," says Camp. "People who have a healthy savings rate know where their money is going because they track it."

Checking in regularly makes it harder for you to let your spending get away from you, says Camp. "You may not have realized before that you're overspending in a certain category," she says. "It's just really hard to let your spending get out of control when you track it so well."

On this front, it may be helpful to use an online budgeting tool, which can help you easily break down your spending into categories. Or go through your financial statements and log your expenses into a good old-fashioned spreadsheet. Either way, the more you do it, the less burdensome it's likely to feel, says Camp.

"Some of these people spend 30 minutes on it a month. But that 30 minutes makes a drastic difference for them," Camp says.

The downsides of financial diligence

Those hoping to retire early generally have a monetary sum they're aiming for, known as their FIRE number. If held in a portfolio, it's the amount of money they'd need to live on without running out of cash.

This number can fluctuate from person to person depending on their goals, desired lifestyle and if they plan to have other sources of income, such as real estate income, once they leave their 9-to-5.

While this kind of planning is essential to reaching your financial goals, fixating on that number at the expense of other aspects of your life can be dangerous, says Camp.

For some people she's spoken with, reaching the FIRE number is, "always top-of-mind," Camp says. But, "to be fair, it's not always a healthy habit."

While some FIRE adherents are naturally and happily frugal, others deprive themselves of things that might improve their quality of life. Some may work a lucrative job that makes them unhappy in order to bank as much as possible.

"Even though they hate their daily lives, that's going to get them to their freedom number faster," says Camp. "I don't advocate for that, and it's probably not the best way to do things."

The amount of effort you're willing to put toward achieving your financial goals will vary from person to person, and there's nothing wrong with being focused on your bottom line. But if other aspects of your life demand more of your mental energy, the best tool to keep your money on track is automation, says Camp.

Setting up automatic contributions to retirement accounts, such as a 401(k) offered through your workplace, guarantees that you're stashing money away without ever having to see it. Setting up bank transfers for your bills on paydays can have the same effect.

"The key to building wealth is consistency," says Camp. "And the best way to get consistency is automate everything you can."

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