I have one Visa card that I have operated for two and a half years linked to my retail bank. I have no plans to close it. I have opened seven new cards in the past 12 months (and about to apply for my eighth). I have closed six of them and will probably close the Amex once I have converted MRs to KrisFlyer in February - although the earn rate with Amex is so good that it seems a pity. By my calculation, there are 10 cards worth churning but it is worth holding one as the daily transaction card.I do around 6 to 7 cards per year (sometimes a little more and sometimes a little less). I'd probably be considered a high frequency churner and then I'm sure there are a few that go through more cards per year.