A credit card is a tool. In the right hands it builds your credit score, protects your purchases and costs you nothing. In the wrong hands it quietly transfers a slice of your salary to a bank every month for years. The difference isn't income — I've watched people on £22k use cards brilliantly and people on £60k drown. The difference is knowing the traps. Here are the five I see most.
1. Paying only the minimum
The minimum payment is designed to keep you in debt as long as legally comfortable. On a £2,000 balance at 24% APR, paying the minimum can take over 15 years and more than double what you borrowed. The card app makes the minimum the default button for a reason. Always pay the full statement balance if you possibly can; if you can't, pay a fixed amount far above the minimum and never let it drift down.
2. Chasing cashback you don't earn back
"2% cashback" sounds like free money until you notice you're spending more to earn it. Rewards cards are profitable for the issuer precisely because most people carry a balance, and the interest dwarfs the rewards. Cashback is only genuinely free if you clear the card in full every single month. If there's any chance you won't, the plain card with the lowest rate beats the shiny rewards card every time.
3. Treating the limit as a target
Your credit limit is the most you can borrow, not a goal to hit. Running close to your limit hurts your credit score (utilisation matters) and leaves no room for a real emergency. A good rule: try to keep your balance under 30% of the limit, and think of the rest as a fire exit, not a spending allowance.
The bank makes money on your patience running out. Every trap on this list is just a bet that you'll pay later, distracted and in a hurry. Slow down and the house edge disappears.
4. Falling for "0% for 18 months"
Zero-percent introductory offers can be genuinely useful — but only with a plan and a calendar reminder. The trap is human: 18 months feels infinite, so you relax, and the balance is still there when the rate leaps to 25%. If you take a 0% deal, divide the balance by the months, pay exactly that every month, and clear it before the deadline. Treat the intro period as a countdown, not a holiday.
5. Ignoring it until it's a problem
The most expensive mistake is avoidance — not checking the balance, not reading the statement, letting a direct debit fail. Interest and fees love inattention. Open the app once a week for sixty seconds. That single boring habit prevents almost every credit card disaster I've ever seen.
Used well, a card is a genuine asset. Used on autopilot, it's a slow leak. If cards have gotten away from you, The Total Money Makeover lays out a step-by-step way back — and it's on our shelf for under a tenner.