Procrastinating on this money move cost me thousands of dollars—actually doing it took 15 minutes

Earlier this year, I transferred two individual retirement accounts — one Roth and one traditional — from one brokerage account to another. Between chatting with someone on the phone and entering information online, it took me all of 15 minutes.

I felt like a moron.

To understand why, we have to back up five years. In 2020, I took a new job at CNBC and left money sitting in my former company's 401(k). Soon, however, that company came under new ownership and rolled everyone's assets — in my case, my Roth account and my employer's pre-tax contributions — into IRAs.

The new brokerage charged hefty transaction fees for many of the funds I wanted to buy. So I parked everything in that broker's branded target-date fund, which came with no fee, and told myself I'd transfer the money over to my preferred broker and invest it in an S&P 500 index fund when I got a chance.

It took me half a decade. Over that period, the fund I invested in logged an annualized return of roughly 12%, compared with an 18.5% return for the S&P 500. Considering the accounts were worth about $65,000 when I transferred them, it's safe to say that my procrastination cost me thousands of dollars.

It's not like I didn't know the fund was underperforming. I was just dreading having to make the rollover, a task which I was certain would involve coordinating two brokerages over endless, frustrating phone calls, or worse — a transfer misstep that would result in tax consequences.

So I just put it off. It's a common mistake, even among capable investors, says Christine Benz, director of personal finance and retirement planning at Morningstar.

"Inertia is by far the most powerful force in the investing landscape," she says. "People are busy. We have complicated lives apart from our financial matters, and it's easy to just let things go, even if you have a sense you could be doing better."

It could have been a lot worse. Many people let the perceived difficulty of building and managing a portfolio keep them from investing altogether, says Amos Nadler, founder of Prof of Wall Street and a Ph.D. in behavioral finance and neuroeconomics.

"It's a bias that we call 'complexity aversion,'" he previously told CNBC Make It. "And it's the biggest barrier to building wealth for people who are not in markets or who have never invested before."

Even if you've taken the steps to open an account, this bias can creep in. You may, for instance, be contributing to a 401(k), but have been putting off choosing from your company's roster of mutual funds, and instead leaving your money in a default, low-yielding cash account. It's a common move that can seriously hurt your finances, says Annamaria Lusardi, director of the Initiative for Financial Decision-Making at Stanford.

"You may feel like you don't know where to start, but if you don't make these decisions, you can end up saving very little and investing poorly," she says. "The problem is, there's no bell that goes off to remind us that this is not good."

So what's the money procrastinator to do? For one thing, give yourself regular financial check-ups, says Lusardi.

"We do it for our car because we're afraid it will leave us on the road. We do it for our health because we want to know if we're doing well or not, and we should do it for our finances, too," she says.

Lusardi recommends yearly check-ins in which you consider your financial goals and assess whether you're taking action to optimally reach them. In my case, an annual review would have presented at least four opportunities to roll over my underperforming IRAs.

Another move Lusardi recommends: enlisting the help of a pro. "Go to your employer and figure out what resources are available," she says. "Chances are, if your employer offers some kind of pension plan, they also offer free consultancy."

If it's a nuts-and-bolts question, like how to execute a trade or how to transfer money without running afoul of tax rules, don't be afraid to call your financial institution's helpline. I could have executed my rollovers entirely online, but it helped to have a representative talk me through the whole process on the phone.

The same inertia that once held you back can eventually work in your favor. Once you set up investing accounts and invest in a portfolio that's right for you, consider setting up automatic transfers into those accounts, either through your bank or via payroll deduction, experts say.

"Do whatever you can do to just put [investing] on autopilot and not think about it again," Benz says. "If you're making contributions to a 401(k) or an IRA or a taxable account and you have automatic contributions, all of that is really powerful."

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