Why YSK: Some banks have no minimum age for authorized users, and report credit usage for them. If you have a credit card you don’t use much, you can add your kids as authorized users, set up a reoccurring payment from the card and an automatic payment to the card, and then forget about it. Your kid could become an adult with an already-maxed credit score.
Also, it’s a double-edged sword. Don’t be adding your kid as an authorized user for convenience and then surprised pikachu when their credit report raises flags for big debt with no income (like my parents did.) An authorized user isn’t just someone who can use the card. Their credit score is affected by any card they’re authorized on.