What nobody tells you
- Not all debt behaves the same — a 3% mortgage and a 25% credit card balance are barely the same category of financial event.
- Minimum payments are calculated to keep you paying for as long as legally possible; they are not a neutral default option.
- Carrying debt doesn't build your credit any faster than paying it off in full each cycle — a persistent myth that costs people real interest.
The basics
- Interest rate is the cost of borrowing, usually expressed as an annual percentage.
- Secured debt (mortgage, auto loan) is backed by an asset the lender can repossess; unsecured debt (most credit cards, personal loans) is not.
- Total cost of debt = principal + all interest paid over the life of the loan, which can be dramatically higher than the amount borrowed for long, high-rate debt.
The framework
Rate vs. return
Compare the interest rate on any debt to the realistic return you'd get by investing that money instead. This single comparison clarifies almost every 'should I pay off debt or invest' question.
- 01
If the debt's rate is higher than a realistic investment return, paying it off is the better guaranteed 'return' available to you.
- 02
If the debt's rate is very low (many mortgages, some subsidized student loans), investing extra money may build more wealth over time — but there's no guarantee, and psychological comfort with debt matters too.
- 03
Debt used to acquire an appreciating or income-producing asset is fundamentally different from debt used to fund consumption that's already gone.
The playbook
Words they use without explaining
- Amortizing loan
- A loan with fixed payments that pay down principal on a set schedule (mortgages, auto loans, most student loans).
- Revolving debt
- Debt with a credit limit you can borrow against repeatedly, like a credit card, with no fixed payoff schedule.
- Avalanche method
- Paying off debts in order from highest to lowest interest rate for the lowest total interest cost.
- Snowball method
- Paying off debts from smallest to largest balance, for psychological momentum.
The mistakes — what people get wrong
- Treating all debt as equally urgent or equally fine — a 22% credit card and a 4% mortgage need completely different strategies.
- Paying only minimums on high-interest debt while investing elsewhere at a lower expected return.
- Taking on new debt to pay off old debt (like a balance transfer) without understanding the new terms and fees.
Ask yourself
- Do I actually know the interest rate on every debt I carry?
- Am I paying only minimums on anything with a rate above what I could reasonably earn investing?
- What did this debt actually buy me, and is that purchase still delivering value?
Go deeper
- Practice
A full debt list with rates, ranked highest to lowest
The single most clarifying exercise for anyone with more than one debt.
- Book
The Psychology of Money — Morgan Housel
Useful context for the emotional, not just mathematical, side of debt decisions.
- Tool
An avalanche vs. snowball payoff calculator
Compares total interest and time under both strategies for your specific debts.
General educational information, not legal, tax, medical, or financial advice. Rules vary by country and change over time — verify with a qualified professional before acting.