When you are added as an authorized user on someone else's credit card, how does it typically affect your credit profile?

Being added as an authorized user typically causes the primary cardholder's account to appear on your credit report, including its complete payment history, age, and utilization. If the account is old, has a high limit, and carries a low balance, it can meaningfully boost your scores. However, negative history on that account can also hurt your report, so it is important to be added only to accounts in good standing.