If you’re decades away from retirement, deciding which account to withdraw from first probably ranks somewhere below reading the fine print on a dishwasher warranty. Fair enough. But there is a reason this matters long before you are actually retired. The mix of accounts you build today can determine how much control future-you has over taxes, healthcare costs, and retirement income.
A 401(k), a regular investment account, and a Roth IRA can all help you build wealth, but the government treats each one differently when money comes back out. If nearly all of your retirement savings eventually land in accounts that create taxable income when withdrawn, you could reach retirement with an impressive balance and surprisingly little control over your tax bill. The goal is not to avoid taxes forever. It is to give yourself options about when and how you pay them.
The Mistake: Draining Taxable Accounts First
One traditional retirement rule of thumb sounds simple: spend your cash and taxable investments first, leave the traditional 401(k) or IRA alone so it can keep growing, and save Roth money for last. That strategy can work, but treating it like a universal rule can create a problem. Traditional retirement money usually has a future tax bill attached to it. You generally received the tax break when the money went in, so withdrawals eventually count as taxable income. If you leave a large traditional balance untouched for decades while draining every other source of money, future-you may eventually have fewer ways to control how much taxable income shows up in a given year.
Think of retirement savings less like one giant pile of money and more like several buckets with different rules. Having money available in more than one bucket gives you choices. In one year, you might pull some money from a traditional IRA and some from a taxable account. In another, Roth money could help cover a major expense without creating the same federal taxable income. Building that flexibility starts years before retirement, which is why younger savers should care about this now instead of waiting until their final paycheck.
Why a Large 401(k) Can Become a Tax Problem
Having $1 million in a 401(k) is a good problem to have, but it helps to understand what that number actually means. If the money is in a traditional 401(k), much of it may never have been taxed as ordinary income. When you eventually withdraw it, the taxable portion generally becomes income for that year. In other words, a $1 million traditional 401(k) and $1 million sitting in a checking account are not economically identical. You still own the retirement account, but part of its future value needs to be thought of as money that may eventually go toward taxes.
This does not mean you should stop contributing to a 401(k). Employer matches and tax-deferred growth can make workplace plans incredibly valuable. The takeaway for someone earlier in life is simply not to confuse “tax deferred” with “tax free.” If nearly everything you save for retirement receives the same tax treatment, you may be giving your older self fewer choices. Over a 30- or 40-year career, building some Roth savings or ordinary investments alongside traditional retirement money can create more flexibility than trying to fix the entire tax picture after you retire.
The Three Retirement Accounts Are Taxed Differently
You do not need an accounting degree to understand the basic idea. Most retirement portfolios eventually contain some combination of three tax buckets. Traditional 401(k)s and traditional IRAs generally give you a tax advantage up front, while taxable withdrawals come later. A regular brokerage account does not give you the same retirement-account deduction, but when you sell an investment you are generally taxed on the gain rather than automatically paying ordinary income tax on every dollar you receive. Investments held long enough may qualify for long-term capital-gains rates.
Roth accounts flip the traditional model around. You contribute money that has already been taxed, and qualifying withdrawals later can generally come out free of federal income tax. Under current law, owners also do not face lifetime required minimum distributions from Roth IRAs or designated Roth accounts in workplace plans. None of these three buckets is automatically “best.” Their value comes from having different rules. If future-you needs $80,000 but can decide how much comes from each tax bucket, you have far more control than someone whose entire retirement is sitting in one traditional account.
Required Minimum Distributions Can Change Everything
Traditional retirement accounts do not necessarily let you postpone taxes forever. Eventually, federal rules can require you to begin withdrawing money through required minimum distributions, better known as RMDs. Under current law, the applicable starting age is generally 73 for people born from 1951 through 1959 and 75 for people born in 1960 or later. The annual amount is largely based on the account balance at the end of the previous year and an IRS life-expectancy factor.
This is where a great savings habit can create an unexpected issue. Imagine spending decades aggressively building a traditional 401(k), retiring with plenty of cash elsewhere, and barely touching that 401(k) for another decade. The account may keep growing, which sounds fantastic until RMDs eventually force taxable money out whether you need it or not. You can reinvest money you do not spend, but the required distribution can still count toward your taxable income. The lesson for younger investors is not “save less.” It is to build enough tax diversity that future withdrawals are something you can manage rather than something that mostly manages you.
Waiting Until Age 75 Isn’t Always an Advantage
If you were born in 1960 or later, current law generally gives you until age 75 before RMD rules kick in. More time for tax-deferred growth sounds like an automatic win, and sometimes it is. But delaying withdrawals can also mean the balance being used to calculate those future RMDs becomes much larger. A hypothetical $1 million account growing at an average 5% annually would become roughly $1.63 million after 10 years if no money came out. Real markets will not deliver a smooth 5% every year, but the example shows the basic trade-off.
That is why retirement planning is not simply about delaying taxes for as long as humanly possible. Sometimes paying some tax earlier can reduce the chance of being forced to recognize a much larger amount of taxable income later. Someone who retires at 65 might have a decade before RMDs begin. Those years can become a planning window for taking smaller withdrawals, converting money to Roth accounts, or otherwise reshaping a retirement portfolio. The younger you are today, the more time you have to build those choices into your savings strategy instead of trying to manufacture them at 70.
A Roth Conversion May Help Reduce Future Taxes
A Roth conversion is basically a trade with your future self. You move money from a traditional retirement account into a Roth account and generally pay income tax on the taxable amount converted that year. In exchange, that money can potentially keep growing in the Roth, with qualifying withdrawals later coming out tax free. You are not magically eliminating the tax bill. You are choosing to recognize some of it now in hopes that doing so gives you a better result or more flexibility later.
The most attractive opportunity can arrive after someone stops working but before Social Security, large pension income, or RMDs push taxable income higher. Those lower-income years may leave room for smaller Roth conversions without jumping as far up the tax brackets. That does not mean everyone should convert their entire 401(k). Going too big in one year can create exactly the tax spike you were trying to avoid. For younger workers, the bigger lesson is simpler: Roth accounts are not just about guessing whether tax rates will be higher someday. They give future-you another type of money to work with.
The Medicare Tax Trap Retirees Often Overlook
Taxes are not the only reason retirement income matters. Medicare can also charge higher-income beneficiaries more for Part B and Part D through something called the income-related monthly adjustment amount, or IRMAA. In 2026, the first surcharge begins above $109,000 in modified adjusted gross income for an individual filer or $218,000 for a married couple filing jointly. Those numbers are adjusted over time, so someone decades from Medicare should treat them as an illustration rather than a future target.
The standard Medicare Part B premium is $202.90 per month in 2026, while beneficiaries at the highest IRMAA level can pay $689.90 per month for Part B, plus an additional surcharge on Part D drug coverage. That is why a giant traditional-account withdrawal or Roth conversion can have consequences beyond the income-tax return. You may make a move that looks smart from one angle and accidentally increase another expense. Future-you will have an easier time navigating that puzzle if you arrive at retirement with multiple sources of money instead of being forced to generate every dollar of spending from taxable retirement withdrawals.
Why Your Income at Age 63 Can Matter at 65
Here is one of the stranger Medicare rules worth filing away for later: the income used to determine an IRMAA surcharge generally comes from your federal tax return from two years earlier. That means 2026 Medicare premiums are usually based on income reported for 2024. Follow the same logic forward and a major financial move shortly before Medicare eligibility can show up in your premiums after you enroll.
For example, someone who makes a very large Roth conversion at age 63 could potentially raise the income Medicare examines when that person is 65. That does not mean age 63 is some magical deadline or that Roth conversions suddenly become bad. It means financial decisions can interact in ways that are not obvious when you look at only one rule at a time. This is another reason younger investors should focus on flexibility. Having traditional, Roth, and taxable money available later can let you choose where cash comes from without creating one giant burst of taxable income whenever life gets expensive.
Retirement Can Qualify You for Medicare Premium Relief
The two-year Medicare lookback can sound especially unfair when someone’s old tax return reflects a salary they no longer earn. Social Security does provide a process for certain situations like that. Stopping work or substantially reducing work hours can qualify as a life-changing event for purposes of requesting a new IRMAA determination. Other qualifying events include marriage, divorce or annulment, the death of a spouse, and certain losses of income-producing property or employer pension income.
Eligible beneficiaries can use Form SSA-44 to ask Social Security to consider more recent income information. That does not mean every temporary income spike can be erased. A voluntary Roth conversion or a great year in the stock market is not automatically a qualifying life-changing event just because it increased Medicare premiums. Still, it is useful future knowledge: if you finally retire and Medicare is charging you based on the much larger salary you earned two years earlier, do not automatically assume you are stuck with that premium forever. There may be a formal process for having it reconsidered.
Blending Withdrawals Could Be a Better Strategy
Retirement withdrawals do not have to work like finishing one drink before opening the next. Someone who needs $100,000 for a year of expenses does not necessarily have to take the entire amount from a traditional IRA or completely drain a brokerage account first. Depending on the situation, that person might combine a smaller traditional withdrawal with cash, taxable investments, and perhaps qualified Roth withdrawals. Each source can affect the tax return differently.
A brokerage sale, for example, may include both the money originally invested and a taxable capital gain. A traditional IRA withdrawal generally creates ordinary taxable income, while a qualifying Roth withdrawal generally does not increase federal taxable income. By mixing those sources, a retiree may be able to stay within a desired tax range or avoid creating one huge income spike. The point is not that there is one perfect percentage to use. It is that having three different tools is usually more useful than reaching retirement with only one giant hammer.
Roth Conversions Can Create Unexpected Tax Bills
Roth conversions sound so attractive that it is easy to forget the first half of the deal: you generally owe tax on the taxable amount you convert. For 2026, married couples filing jointly have a $32,200 standard deduction, and the 22% federal bracket begins once taxable income exceeds $100,800. Someone with salary, pension income, investment income, or other taxable money already filling up the lower brackets could push additional dollars into higher rates with an oversized conversion.
There can be secondary effects too. The 3.8% Net Investment Income Tax generally applies when someone has net investment income and modified adjusted gross income above $200,000 for single or head-of-household filers or $250,000 for married couples filing jointly. Retirement-plan distributions and Roth conversions are not themselves net investment income, but they can increase modified adjusted gross income enough for otherwise taxable investment income to become subject to the additional tax. This is why “convert everything to Roth” is not a strategy. It is a transaction that needs to be sized around the rest of your financial picture.
Review Your Withdrawal Strategy Before It’s Too Late
The useful lesson for a younger person is not that you need to map out withdrawals for 2065 tonight. Tax laws will change, Medicare rules will change, and your career will probably change more than once before retirement. What you can do now is avoid building a future where every dollar has exactly the same tax consequences. If your employer offers both traditional and Roth 401(k) contributions, learn how each works. If you invest outside retirement accounts, understand what that adds to the mix. As your income changes, revisit which bucket you are filling.
Then, as retirement gets closer, the question changes from “How much have I saved?” to “How do I turn this into income without creating unnecessary problems?” That is when RMDs, Social Security, Medicare, capital gains, Roth conversions, and annual spending all start interacting. A financial planner or tax professional can help model the numbers when the time comes. For now, the goal is much simpler: give future-you choices. A retirement account balance tells you how much money you have. A well-diversified tax strategy can help determine how much control you have over it.