If you?ve ever lost a credit card, you know how important it is to know your card number and how to contact the card issuer to report it lost or stolen. I use this spreadsheet to record my card numbers and expiration dates, contact information, etc. If you?ve ever lost a credit card, you know how important it is to know your card number and how to contact the card issuer to report it lost or stolen. I use this spreadsheet to record my card numbers and expiration dates, contact information, bank account and routing numbers, account numbers for monthly bills, and addresses for all of the above accounts. It?s darn handy to have all this info in one place.