I did that too. And then someone ordered $600 worth of telephone equipment delivered to a mail drop in Detroit, my account was billed, my bank paid it automatically and bounced every check I wrote after that. It took two months to get Michigan Bell to reverse the charge - at first they refused to deal with me because I was not the "customer" who ordered the merchandise. And the kicker: my wife worked in Bell's legal department at the time! She had to get the top dogs to intervene - a power an ordinary citizen would have lacked.

As a result, I do not use auto-pay unless I am required to. I will use electronic payments from my bank account, but I like to review them and click the button myself.