[Porsche-O-Phile]

The first thing you should do with any card is white out or otherwise obliterate the 3-digit code on the back. Commit it to memory and/or write it down somewhere and put it in your records. But do NOT leave it on the card. I typically scratch them off completely. That way if the card is compromised it's far less useful to the thief and the potential damage is contained.

Yes, it occasionally is a PITA if I forget it and want to make a phone purchase, but is making buying/spending money inconvenient really such a bad idea? I actually think there are some pretty significant upsides to making it more difficult and inconvenient to spend money.