An authorized user is an individual the primary cardholder allows to use their credit card account to make purchases. Any authorized user receives a card bearing their name and is often entitled to all the benefits of card ownership. However, the primary cardholder is the sole applicant for the credit card and retains responsibility for making all card payments.

There are a number of excellent reasons to add an authorized user to your credit card. Since many credit card issuers have stopped offering joint accounts, adding an authorized user is an easy way to keep your and your partner's spending in the same place.

You may also find it's more cost effective to add an authorized user to a premium card rather than opening two separate accounts. The Platinum Card® from American Express's (Terms apply, see rates & fees) annual fee is $695, but it's only $195 to add an authorized user. For families looking to provide a minor child with card access -- before they can open their own account -- adding them as an authorized user may be the solution. American Express allows you to add children who are 13 years or older.

Another reason many people choose to add an authorized user is to help build credit. Whether you're new to credit or trying to build credit, becoming an authorized user can help improve your score if the primary cardholder practices responsible credit usage. American Express won't report credit behavior for minors. However, once an authorized user turns 18 years old, any positive behavior from the primary cardholder will be reported on the authorized user's behalf, as well.