Once upon a time I was very good at paying off my cc's every month! Then I would only use them for tuition or maybe a vacation, then pay off and they would be inactive for like ever.
Well I just recieved my credit report, it indicates I had 4 or 5 American Express cards, the time active did not overlap for any of them. They would close my account "by creditor" and issue me a newone with a new number everytime.