Maxing your 401(k) feels like a financial achievement — and it is. But if it's the only thing you're doing for retirement, you're leaving real money on the table. The tax code offers multiple retirement savings vehicles, each with different rules and advantages. Using just one is like ordering a steak and ignoring everything else on the menu.
Why One Account Isn't Enough
The 401(k) contribution limit for 2024 is $23,000 ($30,500 if you're 50+). That sounds like a lot, but if you're 35 and want to retire at 65 with $2 million, a maxed 401(k) alone might not get you there — especially if your employer match is modest and returns disappoint.
More importantly: you don't know what tax rates will look like in 30 years. A traditional 401(k) is pre-tax money — you'll owe income tax on every dollar you withdraw. If rates rise, that's a problem. Diversifying across account types (pre-tax, Roth, taxable) gives you flexibility to manage your tax bill in retirement.
The Retirement Account Stack
Here's how to think about priority order:
- 401(k) up to the employer match. This is a guaranteed 50%–100% return on your contribution. Always get the full match first — it's free money.
- Roth IRA ($7,000/year limit for 2024). After the match, most people should contribute here next. Tax-free growth, tax-free withdrawals in retirement. No required minimum distributions (RMDs). More flexible than a 401(k).
- Max the 401(k) ($23,000 total). Once you've funded the Roth IRA, go back and max the 401(k).
- Taxable brokerage account. No contribution limits, no restrictions. Less tax-efficient, but flexible and accessible without penalties before 59½.
See the complete 401(k) guide and Roth vs Traditional IRA breakdown for the full details on each.
The Roth IRA Income Problem (and the Fix)
Roth IRA contributions phase out at higher incomes: $146,000–$161,000 for single filers, $230,000–$240,000 for married filing jointly (2024 limits). If you earn above these thresholds, you can't contribute directly.
Enter the backdoor Roth IRA:
- Contribute to a traditional IRA (non-deductible, no income limit)
- Immediately convert it to a Roth IRA
- Pay tax on any gains (minimal if you convert right away)
This is perfectly legal and widely used. The caveat: if you have other pre-tax IRA money, the pro-rata rule can create an unexpected tax bill. Consult a tax advisor if you have existing traditional IRA funds before doing this.
The HSA: A Stealth Retirement Account
A Health Savings Account (HSA) has a triple tax advantage that no other account matches: contributions are pre-tax, growth is tax-free, and withdrawals for qualified medical expenses are tax-free. But there's a lesser-known feature: after age 65, you can withdraw HSA funds for any reason — just like a traditional IRA. You'll owe income tax, but no penalty.
Meanwhile, healthcare costs in retirement are enormous. The average retired couple needs $300,000+ for out-of-pocket healthcare expenses. An HSA you've been investing for 20 years covers those costs tax-free. See HSA vs FSA: which is worth it for eligibility requirements and strategy.
Taxable Brokerage: The Overlooked Third Bucket
Once you've maxed tax-advantaged accounts, a taxable brokerage account is your next move. No contribution limits. No withdrawal penalties. No required distributions. You invest in the same index funds, but dividends and capital gains are taxable in the year they occur.
The key strategy: hold tax-efficient investments here (index funds, not bond funds). Use tax-loss harvesting. And remember — long-term capital gains rates (0%, 15%, or 20%) are lower than ordinary income rates, so taxable accounts aren't as punishing as they sound.
Diversifying Your Tax Exposure
The goal is to enter retirement with money in all three tax buckets:
| Bucket | Account Types | Tax Treatment in Retirement |
|---|---|---|
| Pre-tax | Traditional 401(k), Traditional IRA | Withdrawals taxed as ordinary income |
| Roth (post-tax) | Roth 401(k), Roth IRA | Withdrawals completely tax-free |
| Taxable | Brokerage account | Dividends/gains taxed at lower capital gains rates |
| Tax-free medical | HSA | Tax-free for medical; ordinary income for other uses after 65 |
With money in each bucket, you can manage your tax bill in retirement by choosing which account to draw from each year — keeping you in lower tax brackets, reducing Medicare IRMAA surcharges, and minimizing the tax on Social Security benefits.
What About Social Security?
Social Security is real retirement income, but treat it as a floor, not a foundation. The average monthly benefit in 2024 is about $1,907. For most people, that covers basic expenses but not the lifestyle they want. Delay claiming until 70 if you can — benefits increase roughly 8% per year between full retirement age (67 for most people) and age 70. That's a guaranteed 24% raise for waiting three years.
How Much Do You Actually Need?
A rough framework: multiply your expected annual retirement expenses by 25. That's your FIRE number (Financial Independence number) based on the 4% safe withdrawal rate. If you expect to spend $80,000/year in retirement, you need ~$2 million. Check how much you should have saved by age to see if you're on track.
The Bottom Line
Your 401(k) is the starting line, not the finish line. Stack accounts in priority order: 401(k) to match → Roth IRA → max 401(k) → HSA → taxable brokerage. Diversify across tax treatments so future rate changes don't blindside you. The people who retire comfortably aren't necessarily the ones who earned the most — they're the ones who used every available tool, consistently, over decades.
Related: FIRE movement, Social Security optimization.
