As a CPA, I Thought I Knew Social Security — Until I Retired. Here Are 5 Costly Blunders Even the Experts Make.

I’m a CPA and personal finance writer with more than 30 years of experience, which includes writing dozens of articles about Social Security.

But when it came time to file for my own Social Security last year, I had to pause.

I thought I knew the system inside and out. But once I moved from the theoretical side of the desk to the retiree side, I realized that the system is filled with invisible tripwires.

There are tax cliffs that aren’t indexed for inflation. There are work limits that can freeze your benefits. There are breakeven myths that sound smart but are actually mathematically illiterate.

If a CPA can get tripped up by these rules, I know it’s happening to everyone else. Here are the five dumbest mistakes I see retirees make — and how I avoided them.

1. Falling for a common tax myth

Most people assume that since they paid taxes on their wages before they went into Social Security, their benefits will be tax-free.

That’s a logical assumption, but only true if you have very little other income.

If you have other income sources — like a pension, withdrawals from a 401(k) or even part-time work — you’ll likely trigger a tax formula commonly called provisional income.

The IRS takes your adjusted gross income, adds any tax-free interest and then adds half of your Social Security benefits. If that number is over $25,000 (for single filers) or $32,000 (for those married filing jointly), you owe taxes on up to 50% of your benefits. If it goes over $34,000 for single filers or $44,000 for joint returns, you owe taxes on up to 85% of your benefits.

Here’s the kicker: These thresholds were set in the 1980s and never adjusted for inflation. They were meant to tax the rich, but today, they hit the middle class. Be prepared for this tax bill because it catches many folks off guard every year.

2. Obsessing over the breakeven age

When I told my friends I was thinking about delaying my benefits claim until I hit age 70, they all said the same thing: “But what if you die?”

They pulled out napkins and calculated my breakeven age — the age I’d have to live to for the bigger checks to beat the smaller, early checks. Usually, the math says you have to live to about 80 to come out ahead.

Here’s the problem with that math: It assumes you are going to die young.

According to the Social Security Administration’s actuarial tables, if you’re a man who has already made it to 65, your average life expectancy is another 18 years (age 83). If you’re a woman, it is nearly 21 years (age 86).

If you claim early at 62 to “get yours” and then live to 90, you cost yourself tens of thousands of dollars in guaranteed, inflation-protected income. Unless you have a serious health issue, betting on your own early death is a bad financial strategy.

3. Working too much (the earnings test)

I have a friend who claimed benefits at 63 but kept his consulting gig. He thought he was double-dipping. Then he got a letter from the SSA telling him they were withholding his checks.

He violated the earnings test.

In 2026, if you claim benefits before your full retirement age, you can only earn $24,480 a year. For every $2 you earn above that limit, the government withholds $1 of your benefits.

They don’t take it forever. They eventually recalculate your benefit when you hit full retirement age to pay you back, but that doesn’t help you pay the electric bill today. If you plan to keep working, don’t claim early if you don’t have to.

4. Stiffing your spouse

I’m the higher earner in my household. If I claim early, I’m permanently capping the survivor benefit my wife will receive if I die first.

When the higher earner dies, the lower earner bumps up to the higher earner’s check. But if the higher earner took a reduced check at 62, the surviving spouse is stuck with that reduced amount for the rest of their life.

If you are the high earner, you aren’t just delaying for yourself. You’re essentially buying a higher lifetime income for your spouse.

5. Setting it and forgetting it

Social Security isn’t a “set it and forget it” income stream.

Every year, there is a cost of living adjustment (COLA). In 2026, it’s 2.8%. But Medicare Part B premiums also rise, and they’re deducted directly from your check.

I check my personal “my Social Security” account online every year. I check the earnings record to make sure they didn’t miss a year of work (which happens more than you think). And I check my tax withholding settings.

If you don’t ask the SSA to withhold taxes from your check (form W-4V), you can get hit with a massive tax bill in April. For many, it’s less painful to have it withheld monthly than to write a big check to the IRS once a year.