I am going to ask another question regarding which CC should I add to my credit card profile to add to my rewards. I have excellent credit, pay my balance in full each month, and I use my CC to pay for everything I can to rack up points/miles etc.

I am at a point where I want to increase my points and miles so there are some options. The question is, what is too much. I basically share a VISA with my wife, and have an older VISA that i keep. I realize that you should keep older credit cards for history. I want to add at least one AM/EX either the Starwood points, or the Delta Miles. I also might switch our Cap1 card to the signature to get 2 points for every $1 spent, instead of 1.25 for $1. That is a new card, not a switch. And recently, I have received letters for UNITED miles (20,000 bonus) and AA Miles (21,000 Bonus). I would love to use those just to add to my miles on those flights. Could I add 3-4 cards without hurting my excellent credit? I will not rack up debt.