I began churning Citi cards last Aug and the sum of all those credit limits is >$56k. The credit limit on my new Amex cards are effected by this sum. I will begin to cancel cards after 6 months which Kaukau suggests in order to avoid forfeiting bonus miles. I think he said B of A was taking back bonuses if accounts were closed in less than 6 months. No word on Citi doing that but I will stick with the 6 month rule.