Avoiding Common 403(b) Mistakes: A Guide for Teachers

Planning for retirement as a K-12 educator involves navigating a unique intersection of state pension benefits, supplemental savings plans, and evolving regulations. Along the way, even well-intentioned teachers make costly mistakes that can reduce their retirement income by thousands of dollars. Here are the seven most common 403(b) mistakes — and how to fix each one.

Mistake #1: Not Contributing Enough to Capture the Full Employer Match

Many districts that offer 403(b) matching contributions will match up to a set percentage of salary — commonly 3% to 6%. Teachers who contribute below that threshold leave free money behind. Consider Marcus, a first-year high school English teacher earning $52,000 whose district matches 50% of contributions up to 6% of salary. If Marcus only contributes 2%, he captures a $520 match. If he contributes the full 6%, he captures $1,560 — a difference of $1,040 per year that compounds over a 30-year career into more than $100,000 in additional retirement savings.

How to Fix It: Contact HR or your benefits administrator to confirm your district's match formula, then set your contribution rate to at least the full match threshold before directing additional savings elsewhere.

Mistake #2: Selecting a High-Fee Vendor by Default

When a new teacher is onboarded, a vendor representative is often the first person to approach them about 403(b) enrollment. Without comparative research, many educators simply choose whoever was most available. That default choice frequently comes with variable annuity products carrying expense ratios of 1.5% to 2.5% — far above the 0.03% to 0.10% available through index fund alternatives on the same district's approved list.

How to Fix It: Before enrolling, request the full approved vendor list from HR and compare total annual fees using 403bCompare.com or your state's publicly available vendor fee schedules. Prioritize vendors that offer no-load index funds with expense ratios below 0.20%.

Mistake #3: Holding a Misallocated Portfolio for Years Without Review

A 28-year-old teacher who opens a 403(b) account and selects a conservative allocation heavy in bonds may not revisit those selections until age 45 or 50. In the interim, that portfolio missed years of equity growth that a younger investor can afford to pursue. The inverse is also common: an educator approaching retirement who remains 90% in equities faces devastating sequence-of-returns risk if markets decline in the final years before they stop working.

How to Fix It: Review your asset allocation at least annually and whenever you experience a major life change. A general guideline — subtract your age from 110 to get a stock allocation percentage. Alternatively, target-date funds automatically rebalance as your retirement date approaches.

Mistake #4: Ignoring the 457(b) Plan Available Through Your District

Many public school teachers have access to both a 403(b) and a 457(b) plan. Unlike with IRAs, the IRS allows you to contribute the full elective deferral limit to each plan independently. In 2026, that means up to $24,500 in the 403(b) and another $24,500 in the 457(b) — a combined $49,000 in pre-tax retirement savings. The 457(b) also has no 10% early withdrawal penalty if you separate from service before age 59½, making it particularly valuable for educators who retire early.

How to Fix It: Ask HR whether your district offers a 457(b) plan. If it does, prioritize maxing out both plans before contributing to a taxable brokerage account.

Mistake #5: Cashing Out an Old 403(b) When Changing Districts

Teachers who move between districts sometimes cash out their 403(b) balance rather than rolling it over. On a $30,000 account, a 35-year-old teacher who cashes out faces a 10% early withdrawal penalty ($3,000) plus income taxes at their marginal rate — potentially consuming 30% to 40% of the balance. More significantly, that $30,000 left invested for 30 years at 7% would have grown to nearly $228,000.

How to Fix It: When leaving a district, initiate a direct rollover to your new employer's 403(b), a 457(b), or a traditional IRA. A direct rollover means the check goes directly to the new custodian — you never receive the funds personally, so no withholding is triggered.

Mistake #6: Not Accounting for the Pension's Income Gap

A state pension provides a reliable income floor, but most pension formulas replace only 50% to 70% of pre-retirement income, and that replacement rate assumes you stay with the same employer for 25 to 30 years. Teachers who move states, take breaks in service, or retire before reaching full benefit thresholds often see significantly lower pension income. Without a robust 403(b) balance, that gap can force difficult compromises in retirement.

How to Fix It: Request a pension benefit estimate from your state retirement system and model what your monthly income would look like at different retirement ages. Use that figure to calculate how much supplemental income your 403(b) and other savings need to provide to meet your target retirement budget.

Mistake #7: Working with a Non-Fiduciary Sales Representative

The 403(b) market has historically attracted insurance and annuity sales representatives who earn commissions on the products they sell. These representatives are held to a suitability standard — they must recommend products that are "suitable" for you — but not a fiduciary standard, which would require them to act in your best interest. The distinction matters: a suitable product may still carry fees significantly higher than comparable alternatives.

How to Fix It: Work with a fee-only, fiduciary financial advisor who charges a flat fee or hourly rate rather than earning commissions. Ask directly: "Are you a fiduciary, and do you earn any compensation from the products you recommend?" A fiduciary must answer both questions honestly.