One of the things I do is every year I call my credit card company and have them issue me a card with a new number. They roll over the balances, no problem. I generally do this if February or March, as I buy from a much wider range of online merchants during the holidays than throughout the year, some of whom with presumably less stringent internal controls than Amazon or other top tier etailers. By February, I have returned anything that needs returning, and I change the cc number. That way, if somebody does hack one of those sites I used, or there is some other shenanigans regarding "harversting" of cc numbers, the number they they have in their database for me is obsolete.