This is general, educational information to help you understand common credit scoring terminology — not personalized financial advice. Specific scoring models and weightings vary and change over time.
Payment history and credit utilization are the two biggest factors
Credit scores are calculated from several factors, but payment history (whether bills have been paid on time) and credit utilization (how much of your available credit is currently being used) are generally the two most heavily weighted factors in common scoring models. Late or missed payments are one of the most damaging things that can happen to a score, and their negative effect generally lingers for years, even after the account is brought current. Utilization — commonly recommended to be kept meaningfully below the total available limit — is calculated at the moment a lender or scoring model checks a credit report, which can be a different, potentially higher number than what's actually paid off in full each month if a statement happens to close while a balance is temporarily high.
Checking your own credit report doesn't hurt your score
A common, persistent myth is that checking your own credit score or report damages it — in reality, checking your own credit is classified as a "soft inquiry" and has no effect on the score at all, regardless of how often it's done. What does affect a score is a "hard inquiry," which happens specifically when a lender checks credit as part of an actual application for new credit (a loan, a new credit card) — this distinction between soft and hard inquiries is worth understanding clearly, since it removes a real, common, and unnecessary hesitation people have about simply monitoring their own credit.
Multiple credit scores exist, and they can differ from each other
There isn't one single, universal credit score — multiple scoring models exist (different versions from different scoring companies), and even the same model can produce a different score depending on which of the three major credit bureaus' data it's calculated from, since not all lenders report to all three bureaus identically. A score from one source can differ meaningfully from a score checked through a different app or service, and this isn't an error — it reflects genuinely different models and data sources, not one of them being wrong.
Length of credit history and credit mix matter, but less than the top two factors
How long credit accounts have been open, and having a reasonable mix of different credit types (credit cards, an installment loan, for instance), both factor into most scoring models, but generally carry less weight than payment history and utilization. This is part of why financial guidance sometimes suggests keeping an old, unused credit card account open rather than closing it — closing it can shorten average account age and reduce total available credit, both of which can modestly affect a score, even if the card itself isn't being actively used.
The one thing people forget
Dispute genuine errors on a credit report directly with the reporting bureau, since factual mistakes — an account that isn't actually yours, an incorrect late payment that was actually paid on time — do happen and can be formally disputed and corrected, which is different from simply having a lower score due to accurately reported financial history. Reviewing credit reports periodically specifically to catch reporting errors, not just to check the score itself, is a genuinely useful habit many people overlook.