I pay my credit card early all the time -- e.g., I use my Citi card for business expenses and immediately pay those expenses once I get the funds from my employer. I never let those expenses go unpaid prior to the statement closing date as doing so would ding my credit score by carrying a high balance. I've never had Citi or AX care, keeping in mind I pay off the balance in full each month regardless. I've never done an analysis to see if all of this spend exceeds what is my credit limit in a given month, so it's possible I just never ran into some sort of T&C that others have.