I am about to become an authorized user on my wife's account so I can build some credit. Once I have that credit established I plan on having 3 cards of my own. As I get those cards, should I stop becoming an AU on my wife's account who has stellar credit (801 fico)? Would having 3 accounts on my own and 3 as an AU on her accounts mean I have 6 open accounts. If that is the case it may be better to have only 1 or 2 under my own name and stay an AU on one of her accounts because of her excellent credit.
6 open accounts would not be a problem. If there are 3 cc that you think are good and you would like in your credit portfolio I say no problem. Get those three and remain an AU on your wife's 3 accounts. At least until your own AAoA is a few years.
BTW: your wife's fico score will have no bearing on how the cards you are AU on effect your scores. For example if you wife had terrible credit (450 fico or something) as long as the AU card had a long clean payment history and low utilization if would effect your scores the same way as if her Fico was 800. This goes the other way as well. If there is high utilization, and lates, or a short age adding your wife's account may even hurt your scores.
TU 810: EQ 813: EX 814 (9/16/09--Loan officer pull)