Money Decisions: The Comparisons Worth Getting Right

Every big either-or money decision looks like a matter of opinion and is actually a matter of one number. Should you claim Social Security at 62 or wait until 70? The waiting version pays far more per month, but the total you collect only pulls ahead at about age 80.4, so the answer is decided by how long you expect to live, not by which check is bigger. That is the whole method, and it runs every comparison in this cluster, including the one people get most wrong, Roth vs Traditional, which you can test in the Roth vs Traditional Calculator.

Look at what that box does. It never tells you to claim early or to wait. It finds the crossover, then hands the decision back to your own life. If your family lives into their late 80s and you are in good health, waiting to 70 wins by a wide margin. If your health is poor, or you need the money at 62 to stop working, claiming early wins. The number is objective. The choice is personal. That split runs through every decision on this page.

The method, once

There are seven comparisons in this pillar, and they all reduce to the same three moves.

1. Write each option as one total over the same time horizon. Not a monthly payment, not a rate in isolation, but the full cost or full value across the same number of years. Two mortgages, both across 30 years. Two job offers, both as take-home after a full year. Two claiming ages, both as dollars collected by age 90.

2. Solve for the input where the two totals are equal. That is the break-even. Sometimes it is an interest rate, sometimes a number of years, sometimes a tax rate, an hourly rate, or a lifespan. It is one number, and it does not depend on your feelings about either option.

3. Decide by which side of that number your real situation sits. Your debt is above the line or below it. You will stay in the house longer than the crossover or shorter. You expect your tax rate in retirement to be higher than today or lower. The break-even sorts the world into two halves. You just place yourself in one of them.

Every calculator this hub links to runs step two for you. Step three is the reader’s, because it always rests on an assumption that cannot be verified in advance: a future market return, a future tax rate, a personal longevity. The calculators surface the crossover and show how it moves when the assumption changes, then leave the choice to the reader.

The rest of this guide walks each row, names the break-even variable, and points you to the deep dive and the calculator that solves it.

1. Pay off debt or invest? The break-even is an interest rate

This is the cleanest of the money break-evens because one side is a sure thing. Paying off a debt is a guaranteed return equal to its interest rate, with no tax and no risk. Clearing a 22% card is worth exactly as much as an investment that returned 22% every year, guaranteed. Nothing safe does that.

So the break-even is a line between two rates: your debt’s rate and the expected after-tax return on investing instead. The rough dividing line is about 8% APR. Above it, paying the debt almost always wins, because you would need the market to reliably beat that hurdle after tax, and it does not. Below it, the two get close, and a low-rate loan can coexist with investing.

Here is the assumption doing the work: the long-run stock market return. The rule of thumb is about 10% a year nominal, roughly 7% after inflation, and the SEC’s Investor.gov is blunt that investing “doesn’t have a set rate of return.” That is an average over decades with wide swings and the real chance of a bad ten years. A guaranteed 12% from paying a card beats a probable 7% from stocks, which is why high-rate debt comes first. One caveat that outranks everything: capture a full employer 401(k) match before either, because a 50-cents-on-the-dollar match is an instant 50% return that no debt payoff beats.

The full sequence is in pay off debt or invest, and the get-out-of-debt plan behind it is in getting out of debt.

2. Rent vs buy? The break-even is years in the home

Buying a home carries big one-time costs: closing costs of roughly 2% to 5% going in, and about 6% in agent and selling costs going out. Those costs are dead money that renting never pays. Buying earns them back slowly, through the principal you pay down and any appreciation.

So the break-even is a number of years. Stay long enough and the equity you build plus the appreciation outrun the transaction costs and the rent you would have paid. Sell too soon and the fees swamp everything, and renting was cheaper. There is no universal “X years,” because the crossover is a live function of your local price-to-rent ratio, the mortgage rate, closing costs, and how fast homes appreciate where you live. A common range people cite is several years, but that is an output, not a fact, and it swings a lot by city.

Computing it for your actual numbers beats trusting a rule of thumb. That is the point of the rent-vs-buy tool, and the buy-side mechanics are covered in buying a home and mortgages.

3. Lease, buy, or finance a car? The break-even is total cost of ownership

A car comparison feels like it is about the monthly payment, and that is the trap. A lease almost always has the lowest monthly payment, which is exactly why it can be the most expensive way to drive over time, because you never stop paying and never own anything.

The break-even here is the five-year total cost of ownership: depreciation, all the payments, insurance and maintenance differences, and what the car is worth at the end. Buying with cash or a loan usually wins that total over a long horizon, because depreciation slows and eventually you own an asset. Leasing can win for someone who trades cars every three years and wants the newest model with a warranty, and treats the extra cost as the price of never dealing with resale.

Line up the five-year totals, not the payments, and the answer usually flips from what the dealer’s monthly quote implies. Run it in the auto-loan calculator against a lease quote for the same car.

4. Roth vs Traditional? The break-even is your tax rate

This is the decision people agonize over, and it collapses to a single comparison: your marginal tax rate today versus your expected rate in retirement. A Roth is funded with after-tax dollars and comes out tax-free. A Traditional deducts now and is taxed on the way out. If your rate is the same in both periods, they end in a dead heat.

The engine behind the Roth vs Traditional Calculator makes the tie visible. Put $7,000 a year for 30 years at 7% into each, and if your tax rate is 22% now and 22% in retirement, the Roth ends at $707,511 and the Traditional at $707,511, within a few dollars of each other. The tax rate is the break-even, so equal rates are a wash.

Tilt the rate and one side pulls ahead. Expect a lower rate in retirement, say 12% instead of 22%, and the Traditional wins: $798,218 against the Roth’s $707,511, a gap of about $90,707, because you deducted at 22% and paid back at 12%. Flip it, expect a higher rate later, and the Roth wins by the same logic.

For the “now” side of that comparison you can use hard numbers. The 2026 federal brackets, single filer, run 10% up to $12,400, 12% to $50,400, 22% to $105,700, and 24% to $201,775 (IRS, 2026 tax inflation adjustments). The “later” side is a forecast, and that is the catch: current law under the One Big Beautiful Bill amendments is what it is today, but tax law changes, which is itself an argument for holding some of each. Do not let anyone tell you one is universally better.

5. Salary vs contract rate? The break-even is a loaded hourly rate

A $100,000 salary and a $100,000-of-billings contract are not the same money, and the gap is bigger than most people guess. A W-2 employee splits payroll tax with the employer, who quietly pays half. A 1099 contractor pays the whole thing: self-employment tax of 15.3%, which is 12.4% for Social Security plus 2.9% for Medicare, charged on 92.35% of net earnings (IRS Topic 751). The Social Security piece stops at the 2026 wage base of $184,500; the Medicare piece never stops.

That is only the start. The contractor also loses paid time off, the employer share of health insurance, and any 401(k) match, and pays for their own coverage. So the break-even is the hourly rate at which the 1099 net finally equals the W-2 net after all of that. A workable rule: take the salary, divide by roughly 1,800 to 2,000 billable hours in a year, then multiply by about 1.25 to 1.4 to cover the extra tax and lost benefits. A $100,000 salary lands somewhere near $65 to $75 an hour just to break even, not the $50 that a naive divide-by-2,080 suggests.

The deep version, with the exact self-employment math, is in salary vs contract rate, paired with the hourly-to-salary and self-employment-tax tools.

6. One job offer vs another? The break-even is take-home after cost of living

A bigger salary in a more expensive city can leave you poorer, and the sticker number hides it completely. Two things eat the raise before you see it: state income tax, which ranges from zero in Texas or Florida to double-digit top rates in California, and the cost of living, which can differ by 50% or more between metros.

The break-even is your real take-home: the after-tax paycheck divided by a cost-of-living index. A $120,000 offer in a city that costs 50% more than the national average has less real buying power than a $95,000 offer in an average-cost city with no state tax. The nominal salary lost, even though it looked 26% bigger. Compare the two offers on after-tax dollars adjusted for what a normal life costs where you would live, not on the headline.

The method, with real state-tax and cost-of-living numbers, is in comparing two job offers in two cities, using the cost-of-living and take-home-pay tools.

7. Social Security 62 vs 67 vs 70? The break-even is your lifespan

Back to the decision we opened with, now that the method is clear. Claiming at 62 with a full retirement age of 67 permanently cuts the benefit to 70% of your PIA, a roughly 30% reduction. Waiting past full retirement age earns delayed retirement credits of 8% a year, so waiting all the way to 70 lifts the benefit to 124% of the PIA (SSA). Every year of waiting buys a bigger check for life, plus a 2.8% cost-of-living adjustment on top for 2026 (SSA 2026 COLA fact sheet).

The break-even is the crossover age from the StatHero above, about 80.4 on a $2,000 PIA. The early claimer banks $134,400 before the 70-claimer sees a dollar, and the 70-claimer’s $1,080-a-month edge takes about 10.4 years to erase that head start. Cross that age and waiting pulls ahead and never looks back, because the bigger check keeps compounding for the rest of a long life.

One number, then your own situation. The deep version, including spousal and survivor angles, is in the Social Security claiming guide alongside the retirement calculator.

The honest caveat

These break-evens are clean because they are simplified, and you should know exactly what got left out. The Social Security example ignores two real things. It ignores the 2.8% annual COLA, which barely moves the crossover because it scales all three claiming ages together. And it ignores investing the early checks, which does move it, pushing the break-even into the mid-80s or later if the 62-claimer invests every payment and earns a solid return. State the simple crossover of about 80.4, then know that reinvestment can push it years later. The 30% reduction and 124%-at-70 figures also assume a full retirement age of exactly 67, which holds for anyone born in 1960 or later; if you were born between 1955 and 1959 your reduction at 62 is smaller and your maximum at 70 is below 124%.

The bigger honesty point runs through every decision here. The break-even is objective, but the decision is not, because it always rests on an assumption you cannot verify in advance. The market return in the debt-vs-invest line is a long-run average of about 7% real, not a promise, and Investor.gov says so plainly. Your tax rate in retirement is a forecast. Your own lifespan is unknowable. So the right way to use any of these is to find the crossover, then ask how it shifts if the assumption is worse than you hoped, and give yourself margin. A universal winner does not exist. The right answer is the one that fits which side of the number your real life falls on.

Start with the decision in front of you. Test the tax-rate break-even in the Roth vs Traditional Calculator, then work through the deep dives: pay off debt or invest for the 8% line, lease vs buy vs finance a car for total cost of ownership, salary vs contract rate for the loaded hourly rate, and comparing two job offers in two cities for real take-home. Same method every time: find the number, then decide against your own life.

Common questions

What is a break-even in a money decision?

It is the value of one input at which two options cost or return exactly the same. Below it, one side wins; above it, the other does. For Social Security at 62 vs 70 on a $2,000 benefit, the break-even is an age, about 80.4: live longer and waiting wins, die sooner and claiming early wins. The number is objective; the decision depends on which side of it your real situation falls.

At what interest rate should I pay off debt instead of investing?

About 8% APR is the rough line. Paying a debt is a guaranteed, tax-free return equal to its rate, while the stock market averages roughly 7% after inflation with real risk and no guarantee. Above 8%, pay the debt. Below it, investing has a real shot. Capture any full employer 401(k) match first, since a 50% match beats both.

How do I know if Roth or Traditional is better?

Compare your marginal tax rate today with the rate you expect in retirement. If your future rate will be higher, the Roth wins because you lock in your lower current rate. If it will be lower, the Traditional wins. If the two rates match, they end within a few dollars of each other, as the $707,511 vs $707,511 example shows. The “later” rate is a forecast, which is an argument for holding some of each.