Does someone need a durable power of attorney for finances if all his assets are held jointly with his spouse?

If your father, for example, and his present spouse, have all their income and assets under both their names, it may not seem as if there's any need for a power of attorney for finances. If something happens to your father, the spouse already has authority over the assets. But a durable power of attorney for finances is still a good idea. That's because one spouse may become incapacitated at the same time, or soon after, the other. Or, a separate asset or income might later come to your parent without his spouse's name on it.