That's what I do. I set up debit account and put the money in the account. Then buy and use up all the money. If my No. get's used then I have no money for them to steal. You can't be too careful. Pretty much doesn't matter how well you protect yourself, someone out there can get what they need. Whether it be shredding old bills (they can steal out of your mailbox instead) or using a corded phone (wire taps are just old tech) I always try to shop at the same places and buy local whenever possible.
Keep a close eye on you statment's too. Some crooks won't rack up large amount purchases at once because you will notice. But if they spend a twenty dollars here and there every few months, a lot of people will miss that and go on paying it. Never canceling the card. ifa crook get's a few dozen card No., He's got it really going on.