Eventually, most businesses are audited, and when the IRS comes knocking, you may be required to produce business records going back three or more years. If the IRS suspects fraud, they can go back 10 years or more. There is no statute of limitations for tax fraud. If you have lost your backup financial data because of a fire or flood or some other kind of disaster, you can ask the IRS to take your word for it. Don't bet on it, though.
States have their own regulations affecting business resumption planning.
All businesses have contracts, and some contracts require suppliers to perform, come hell or high water. Banks, insurances companies, large manufacturers, and other sophisticated businesses already know the importance of business resumption planning. Many have been practicing this discipline for five or 10 years, and they do not want to be the weak link in their business chain. They do not what to go down because a supplier failed to deliver after a disaster. Often, they contractually require that their suppliers have business resumption capabilities.