That would be the simplest approach, but unfortunately, this is not the case. For any accounts that are joint with your spouse (usually bank accounts, like savings, checking, and CD’s), then yes, even if you are in the hospital or develop dementia, your spouse can manage those accounts.
But what about accounts that are in your name alone? Like your IRA and 401(k), for starters? And that Christmas account that you opened a few years ago, the one your spouse doesn’t even know about? If you are the only owner of an account, then you are the only one who can access those funds. Your spouse cannot help you with your accounts – unless you name him as an Agent under your Durable Power of Attorney (POA).
Only after you (1) name your spouse as an Agent in your Durable Power of Attorney and (2) contact your bank or financial institution to have him listed as a POA on the account, can your spouse then help you manage your accounts in the event you become hospitalized or otherwise unable to manage your finances.
If you develop dementia and have accounts in your name alone, and if your family needs to access those accounts for your care, then your family will be forced to go to court to establish a “Conservatorship” over you. That costs a lot of money (your money, by the way), and takes a lot of time and emotional energy.
Moral of the story? Put a Power of Attorney in place now. It doesn’t take much time at all.