Understanding Credit: Scores, Utilization, and Debt

A credit score is a single number summarizing how risky you look to a lender — and it directly determines the interest rate you're offered on mortgages, car loans, and credit cards. A meaningfully better score can save tens of thousands of dollars over a mortgage's lifetime.

What actually moves your score

The most commonly used scoring models weight a few factors heavily:

• Payment history — the single largest factor; on-time payments matter more than almost anything else
• Credit utilization — how much of your available credit you're using; staying well under 30% of any credit limit is a common guideline, and lower is generally better
• Length of credit history — longer, well-managed history helps
• Credit mix and new credit — smaller factors, but opening many new accounts in a short window can hurt

The utilization trap

A common mistake: paying off a credit card in full every month (good) while still carrying a high balance right before the statement closing date, which is what gets reported. Utilization is measured at a point in time, not your average balance across the month — so a large purchase timed poorly can temporarily depress a score even with perfect payment history.

"Good debt" vs. "bad debt"

Not all debt is equally harmful — the useful distinction is whether the debt finances something that grows in value or earning power (a mortgage on an appreciating home, a loan for education that raises earning potential) versus debt that finances a depreciating purchase at a high interest rate (a large credit card balance carried month to month, generally at 20%+ APR). The interest rate and what's being financed matter far more than the label "debt" itself.

Why this connects to the rest of this track

Credit access and interest rates are a direct application of the interest rate mechanics covered in the Economics track — a lender is pricing the risk of not being repaid, and your credit profile is the primary input to that pricing.

Next: Saving and Compound Interest.