3-4 months to show that they're paid off.
DO NOT CLOSE YOUR CREDIT CARD ACCOUNTS!!!!!
every time you close an account your credit gets "dinged" 30 points!!
DO NOT open another credit card!! this will also ding your credit about 30 points.
having open accounts with a zero balance tells mr. fico that you are mature and responsible, and can handle credit. this is good!!
in a few years, if no activity has occurred on the cards, the company may contact you and say: do this or we're closing the account.
if you want to keep the card, make the necessary purchase, and pay it off the next month to keep the account active.
OTHERWISE, let the company close the account. this HELPS your credit.