When people start chasing financial independence or early retirement, the conversation usually jumps straight to savings rates, investment returns, or which index fund to buy. Those things matter, but they’re only half the story. Just as important is where you invest your money and how those accounts work together over time.

That’s why I invited Sean Mullaney on the show. Sean is an advice-only financial planner, tax expert, and coauthor of Tax Planning to and Through Early Retirement. His work focuses on helping early retirees legally minimize taxes and design withdrawal strategies that create flexibility instead of friction. You can find his work at FI Tax Guy.

When I asked Sean what investment accounts matter most for financial independence, he didn’t hesitate. He said that for most people pursuing early retirement, success comes down to what he calls the Compelling Three.

Sean explained that the traditional 401k, the Roth IRA, and the taxable brokerage account “especially in combination, can be very effective for the potential early retiree as the quickest way to build financial wealth and security.”

Let’s walk through each one and why they matter.

Why a traditional 401k still belongs in early retirement plans

At first glance, a traditional 401k doesn’t look like an early retirement tool. Withdrawals before age 59½ generally come with a 10% penalty, which leads many people to underfund these accounts if early retirement is their goal.

Sean argues that’s often a mistake.

He emphasized that the traditional 401k is powerful because of tax timing. As he put it, most Americans pay their highest taxes during their working years, not in retirement. Contributing to a traditional 401k allows you to deduct money at your highest marginal tax rate, which for many people ends up being the highest rate they’ll ever pay in their lifetime.

Sean also addressed the concern around early access directly. He explained that while the 10% penalty exists as a general rule, “there are many usable exceptions” that early retirees can plan around. These include the Rule of 55, governmental 457 plans, and 72(t) payment plans, also known as substantially equal periodic payments.

He noted that for many early retirees, rolling old workplace plans into a traditional IRA and setting up a 72(t) plan is a very viable option. In his words, these plans “are actually not that onerous” when implemented correctly and can allow access to retirement funds well before 59½.

This section of the conversation hit home for me. Like many people who’ve changed jobs over the years, I rolled multiple 401ks into traditional IRAs. For a long time, I worried that this concentration would limit my early retirement flexibility. Sean’s explanation helped reframe that concern. Those accounts can still play a central role if they’re paired with the right strategy.

The Roth IRA as flexibility and tax insurance

If the traditional 401k is about tax efficiency during your working years, the Roth IRA is about control in retirement.

Sean highlighted that one of the biggest advantages of a Roth IRA is how withdrawals are treated before age 59½. He explained that the IRS requires Roth withdrawals to come from contributions first, and those contributions “come out tax and penalty free at any time for any reason.”

That ordering rule makes Roth IRAs uniquely valuable for early retirees. Someone who has contributed consistently for a decade may have tens of thousands of dollars available to tap without triggering taxes or penalties.

Sean also emphasized the Roth IRA’s role as tax insurance. Growth inside the Roth is tax free, and qualified withdrawals remain tax free for life. That creates a pool of money that doesn’t increase your taxable income, which can be incredibly useful when managing tax brackets, health insurance subsidies, or one-time expenses in early retirement.

He gave a practical example. If an early retiree needs to replace a car or cover a large repair expense in their early 50s, the Roth IRA can fund that cost without forcing a taxable withdrawal from other accounts.

Sean also addressed why he generally prefers Roth IRAs at home and traditional accounts at work. He pointed out that many people with workplace retirement plans cannot deduct traditional IRA contributions anyway, which makes Roth IRAs a cleaner and more efficient option for after-tax savings.

Why taxable brokerage accounts matter more than people realize

The third leg of the Compelling Three is the taxable brokerage account, and it’s often the most misunderstood.

Sean explained that taxable accounts are especially powerful in early retirement because of how income is calculated. When you sell investments in a taxable account, only the gains are taxable. Your original contributions, known as basis, are returned tax free.

He also pointed out that long-term capital gains rates can be extremely favorable for early retirees. In many cases, people can realize gains at a 0% federal tax rate if their taxable income stays below certain thresholds.

That combination makes taxable accounts ideal for funding the first several years of early retirement. Sean explained that selling assets while recovering basis keeps reported income low, which opens the door to additional planning opportunities like Roth conversions or Affordable Care Act premium tax credits.

At the same time, Sean cautioned against prioritizing taxable accounts over retirement accounts during your working years. He cited three reasons: employer matches, creditor protection, and tax rate arbitrage. As he put it, deducting contributions at a high marginal rate and later withdrawing them at lower rates is “printing money off the IRS.”

This balance is especially relevant for people pursuing early retirement or Coast FIRE. If your traditional retirement is already on track, directing additional savings into taxable accounts can create a flexible bridge. Tools like our Coast FIRE Calculator and our detailed article on Coast FIRE by age 30, 40, and 50 can help model when that shift makes sense.

There is no perfect account ratio

One of Sean’s most important insights was that there is no perfect percentage split between traditional, Roth, and taxable accounts.

Instead of aiming for an ideal balance sheet, he encouraged people to think about their future tax return. His goal for early retirees is to arrive at retirement with a low-income tax profile that allows flexibility and planning.

Sean explained that an early retiree with mostly equity investments might show only modest qualified dividends and minimal interest income in the first few years. That creates what he called an “ideal tax return” and allows room for strategic withdrawals, Roth conversions, or capital gains harvesting.

If you want to visualize how different account balances affect your timeline and taxes, ProjectionLab is a powerful tool for modeling these scenarios in detail.

Where HSAs fit into early retirement planning

Health Savings Accounts often come up in financial independence discussions, and Sean offered a measured take.

He acknowledged that HSAs can be very powerful, especially because contributions are deductible and qualified medical withdrawals are tax free. However, he also noted that HSAs are more restrictive than the Compelling Three, since penalty-free access is largely limited to medical expenses before age 65.

Sean views HSAs as a complement, not a replacement. In early retirement, they can be especially useful for covering healthcare costs without increasing taxable income, but they shouldn’t crowd out contributions to more flexible accounts.

When to consider professional guidance

Tax planning for early retirement can get complicated quickly. While calculators are helpful, there’s also value in personalized advice.

For those who want flat-fee, advice-only help without asset management pressure, Nectarine connects investors with fiduciary planners who specialize in exactly these questions.

You can also explore scenario testing with tools featured in the best retirement calculators to pressure-test your assumptions.

Financial independence is about options, not just numbers

Toward the end of our conversation, Sean zoomed out from tactics and talked about purpose. Financial independence isn’t about quitting work at all costs. It’s about creating options.

With the right mix of accounts, you gain the flexibility to pursue meaningful work, scale back stress, give generously, or simply spend more time with family. The technical planning exists to support those life choices, not replace them.

For readers who want to go deeper into the tax side of early retirement, Sean’s book Tax Planning to and Through Retirement breaks these concepts down in a practical, approachable way. You can find it here: Tax Planning to and Through Retirement.

And if your broader goal is to design a life with more flexibility and intention, you can learn more about my book Own Your Time here: Own Your Time.

The best investment accounts for financial independence aren’t about finding a single perfect answer. They’re about building a system that gives you control, flexibility, and confidence as you move toward early retirement.

NOTE: The discussion is intended to be for general educational purposes and is not tax, legal, or investment advice for any individual. Andy and Marriage Kids and Money do not endorse Sean Mullaney, Mullaney Financial & Tax, Inc. and their services.