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How long have you had the card, and how long have you been using it this way?
In any event the Chase card is not the best card for buying from Amazon. You would generate more rewards with the Citi Forward card which awards 5 points per dollar on purchases from bookstores (including everything purchased from Amazon), music stores (including iTunes), restaurants, and cinema tickets.
I will apply for Citi Forward card, it seems a pretty good deal.
But do you know how this kind of using-a-lot-of-credit behavior will affect my relationship with Chase and other banks?
Thank you in advance.