The banks have taken the Y2K problem seriously and are ahead of many other institutions in their reparation. They do however recommend keeping hard copy receipts for all your records. Keep copies of all bank statements, mortgage, car and rental payments, IRA's and other records. Keep cancelled checks or carbons. The burden of proof would be on the individual.
Cash is best in an emergency.
If you have electronic locks you might want to check if there is a manual override. There has been some concern about transportation. A full fuel tank in your car is a good idea, but storing gasoline is a bad idea due the hazardous nature of storing this fuel. Some people predict significant plane and train delays so plan accordingly. We intend the above suggestions to be thought-provoking and give general information.