"I have excellent credit, while my fiance's is not so great ... He has about 7 thousand in credit card debt on two cards with a total credit limit of 14 thousand dollars or so. Because of that he's been unable and unwilling to get into mileage game. Would adding him as an authorized user on one or more of my cards bump up his credit at all? It takes twice the time to earn amazing vacations if only one of us can get the credit!"
In short, yes - your husband will benefit by being added as an authorized user on your credit cards as long as they are being paid on time and the balances kept low. Authorized users are reported to all of the major credit reporting bureaus, so he will probably see a bump in his score due to adding more positive accounts to his credit report. Check out this post on how FICO scores are calculated - he will also benefit from the length of time you've had your accounts in good standing.
This is also a great way for parents to help build their children's credit. Most card issuers will allow you to set a limit on the amount an authorized user can spend, so you don't have to worry about them spending past an amount you are comfortable with. Adding a user who has bad credit will not negatively affect yours, as long as everything is paid on time and your debt to available credit ratio does not spike up.
In general, while credit cards can be the keys to the mileage and points kingdom, you should really do research if you are carrying balances. While getting mileage bonuses may be tempting, depending on the balance you carry, it may make sense to get a card with 0% APR (like the Chase Slate card) so you can work to pay off the balance while it is interest free (note: there is a 3% balance transfer fee so do the math to make sure it would make sense).
[card card-name='Chase Sapphire Preferred® Card' card-id='22125056' type='javascript' bullet-id='1']
