I don't let it get down to $0. I leave at least $5 in available cash. I usually have more in the account since I do 2 cycles, but I pull it out to re-cycle as soon as it's available. Has anyone tried to sign up for the American Express promo recently? I had a friend try and the link is now dead. I know AA was supposed to end 9/30, but I thought Amex was through 12/31. Anyone know anything about that?