What Is Debt, and Which Kinds Are "Good" vs "Bad"?

Debt is simply money you owe someone else, with an agreement to pay it back — usually with interest added on top. That's it. The word carries a lot of stress, but the mechanics are always the same: you get money or an asset now, and you commit future income to paying it off.

What actually matters isn't whether you have debt — it's what that debt did for you, and what it's costing you to keep it.

"Good" debt: usually building or preserving something

This isn't an official classification — it's a practical lens. Debt tends to sit on the better end of the spectrum when it meets most of these:

• It's tied to an appreciating or income-generating asset. A bond on a home you'll live in for years, or that you could rent out, is a common example — the debt is attached to something that (usually) holds or grows in value.
• The interest rate is relatively low. Bonds, in particular, are secured against the property, which is why bond interest rates tend to sit well below unsecured credit.
• It has a clear end date and a repayment plan you can see the end of.

"Bad" debt: usually just a cost

Debt tends to sit on the worse end when:

• It financed something that's already lost value or been consumed by the time you're still paying it off — a lifestyle expense, a holiday, or a depreciating asset bought at a high rate.
• The interest rate is high, which is typical of unsecured, uncollateralised credit like credit cards, store cards, and short-term loans — the lender is taking on more risk with nothing to repossess, and prices that risk into the rate.
• It's revolving, meaning there's no fixed end date unless you actively pay it down — the minimum payment can keep you in debt indefinitely while interest keeps accruing.

The framework isn't a rule, it's a question

"Good" and "bad" are useful shorthand, not a strict rulebook. A car loan can be a reasonable, necessary debt if a car is how you get to work and there's no viable alternative — even though a car depreciates. A bond can still be a heavy burden if it's stretched past what a household can comfortably absorb. The more useful question for any debt on your name right now is simply: what is this actually costing me, and what did it get me?

The next lesson looks at exactly how that cost is calculated — how interest actually works on the kind of revolving credit (credit cards, store accounts) that tends to sit on the "bad" end of this spectrum.