Most people set up their 401k once during onboarding, pick a contribution percentage that felt reasonable at the time, and never look at it again. That set-and-forget approach is better than nothing — but leaving a few specific decisions unmade costs thousands of dollars in free money, tax savings, and compounding that never get recovered. Here’s the complete checklist for a 401k that’s actually working as hard as it should.
Step One: Capture the Full Employer Match
If your employer matches contributions and you’re contributing below the match threshold, you are leaving free money on the table every paycheck. This is the single most important 401k decision you can make.
A common match structure: 50% of contributions up to 6% of salary. If you earn $70,000 and contribute 6% ($4,200), your employer adds $2,100 — a guaranteed 50% return on those dollars before any investment growth. Nothing else in finance offers this. Prioritise capturing the full match above every other financial goal except a starter emergency fund.
To find your match formula, check your benefits documentation, the HR portal, or ask your HR contact directly. The formula varies widely: some employers match dollar-for-dollar up to 3%, others match 50% up to 8%. Whatever it is, identify the percentage you need to contribute to capture it completely, then set your contribution to at least that level today if you haven’t already.
Traditional vs Roth 401k: Which to Choose
Many employers now offer both a traditional (pre-tax) and Roth (post-tax) 401k option. The choice comes down to one question: do you expect your tax rate to be higher now or in retirement?
- Traditional 401k — contributions reduce your taxable income today. You pay taxes when you withdraw in retirement. Best if you expect a lower tax rate in retirement than your current rate.
- Roth 401k — contributions are after-tax. The money grows and withdraws completely tax-free. Best if you expect a similar or higher tax rate in retirement, or if you’re early in your career and in a lower bracket now than you’ll be later.
For most people in their 20s and early 30s, the Roth 401k is the better choice — you’re likely in a lower bracket now than you’ll be in peak earning years, and tax-free compounding over 30+ years is extremely valuable. For higher earners in the 32%+ bracket who expect a lower rate in retirement, the traditional option’s immediate deduction makes more sense. If you’re unsure, splitting contributions between both (if allowed) hedges the tax bet.
What to Actually Invest In
This is where most people are leaving money on the table without realising it. Many 401k plans have 20 to 30 fund options, and the default selection (often a money market or stable value fund) is frequently not the right one for long-term growth.
For most people, the right approach is simple:
- Target-date fund — if your plan has one, this is usually the best single-fund option. Pick the fund closest to your retirement year (e.g., “2055 Fund” if you’re planning to retire around 2055). It automatically rebalances from growth-oriented to conservative as you approach retirement. Low-effort, well-diversified, appropriate for most people.
- Three-fund portfolio — if you want more control: a total US market index fund + an international index fund + a bond index fund. Aim for expense ratios below 0.1% — avoid any actively managed fund with expense ratios above 0.5%. The fee difference compounds over decades into enormous amounts.
Check your current fund selection and its expense ratio right now. If you’re in a fund charging 0.8% or more annually, switching to a comparable index fund at 0.05% saves thousands over a career.
Set Up Automatic Escalation
Many 401k plans offer an automatic escalation feature — your contribution rate automatically increases by 1 percent per year until it reaches a cap you set. If your plan has this, enable it now. It’s one of the best financial habits you can build on autopilot: each year, your savings rate increases slightly before lifestyle has a chance to expand to absorb the raise. Over five years, a 3% starting contribution becomes 8% without any annual decision.
If your plan doesn’t offer automatic escalation, set a calendar reminder each January to manually increase your contribution rate by 1 percentage point. It’s one two-minute action per year that compounds significantly over a career.
Check Your Beneficiary Designations
Your 401k passes to whoever is listed as the beneficiary — regardless of what your will says. If you named an ex-partner at a previous job and never updated it, that’s who receives the account when you die. This happens more often than you’d think.
Log into your 401k account and check the beneficiary section right now. Update it to reflect your current wishes. Do this after every major life change: marriage, divorce, having a child, death of a named beneficiary. It takes three minutes and cannot be corrected after the fact.
What to Do With an Old 401k From a Previous Job
If you’ve changed jobs, you likely have one or more old 401k accounts sitting somewhere. Your options:
- Roll it into your current employer’s 401k — simplifies consolidation, keeps everything in one place, but you’re limited to the current plan’s fund options
- Roll it into an IRA — more fund options, lower potential expense ratios, more flexibility. This is usually the best option for most people.
- Leave it where it is — fine if the old plan has great funds and low fees, but inconvenient to manage long-term
- Cash it out — triggers income tax on the full amount plus a 10% penalty if you’re under 59½. Almost never the right choice.
The IRA rollover is usually the winner: you get full control over the investment options and can move to a low-cost provider like Fidelity, Vanguard, or Schwab where index funds are available at near-zero expense ratios. Initiate a direct rollover (account to account, never taking possession of the money yourself) to avoid triggering taxes.
The 401k Optimisation Checklist
Run through this list right now and fix anything that needs fixing:
- ☐ Contributing enough to capture the full employer match? If not — increase the contribution today.
- ☐ Correct fund selection with expense ratios below 0.2%? If not — identify the lowest-cost index fund or target-date fund available and switch.
- ☐ Traditional vs Roth decision made deliberately? If you’ve never thought about it — consider Roth if you’re in the 22% bracket or below.
- ☐ Automatic escalation enabled? If available — turn it on. If not — set a January calendar reminder to increase by 1%.
- ☐ Beneficiary designations current? Log in and check. Update if life circumstances have changed.
- ☐ Old 401k accounts sitting at previous employers? Initiate an IRA rollover if you haven’t consolidated them.
Most of these take five minutes each. The combined impact — full match captured, low-cost funds, escalating contributions, correct beneficiaries, consolidated accounts — represents tens of thousands of dollars of difference over a career compared to the default set-it-and-forget-it approach most people take. This is a Sunday-afternoon financial task that compounds for decades. Do it this weekend.
The 401k Contribution Limit Worth Knowing
The 2025 employee contribution limit is $23,500. If you’re 50 or older, you can contribute an additional $7,500 catch-up contribution, for a total of $31,000. Most people are nowhere near these limits — the median 401k contribution rate is around 7% of salary — but knowing the ceiling helps you understand how much room exists to grow contributions as income rises. The employer match does not count toward your personal contribution limit. A generous employer match effectively increases the total retirement contribution well above what your personal contributions reflect.
Your 401k is probably the largest single financial asset you’ll build over a career. The decisions inside it — contribution rate, fund selection, match capture, escalation, beneficiary — are not set-and-forget choices. They’re the levers that determine whether the account works as hard as it should. Spend an hour on them this weekend. The compounding on that hour runs for decades.
Log in to your 401k account this weekend — not just to check the balance, but to actively verify every item on the checklist above. The 401k is the highest-leverage financial account most people have access to. It deserves more than a glance at the quarterly statement. Give it an hour. The compounding on that hour runs for decades.
The match, the fund, the escalation, the beneficiary — four decisions, each taking minutes, each with decades of compounding behind it.
