What actually hurts
Late payments are the biggest. One payment 30+ days late can cost a healthy score 60–100 points and stays seven years. High utilization is second — balances above about 30% of your limits, and especially a maxed-out card.
Collections, charge-offs, and bankruptcies hurt, but they fade over time. Closing your oldest card can hurt too, by shortening your history and raising utilization. Applying for lots of new credit at once adds hard inquiries and lowers your average account age.
What doesn't hurt (the myths)
Checking your own credit doesn't hurt it — that's a soft pull. Carrying a balance 'to build credit' doesn't help; it just costs interest (pay in full). Your income, your bank balance, and your debit-card use aren't in your credit score at all.
A single hard inquiry costs only a few points and fades within a year. And disputing an inaccurate item never hurts your score.
Why a score drops out of nowhere
Usually it's one of a few things: a balance reported higher than usual, a payment that slipped, a card you closed, or a new account or inquiry. Pull your report and you can almost always find the cause.
The short version
Pay on time, keep utilization low, keep old accounts open, and apply sparingly. Ignore the myths. That's most of the game.
Knowing what matters means you stop wasting effort on what doesn't. Subefy shows you exactly what's helping and hurting your file across all three bureaus, in plain language. Educational only — results vary and no outcome is guaranteed.