The easiest way of doing this is to assume time will never travel and store the latest computed date right? If you've seen 2001, it's never going to be 1999 aga

The easiest way of doing this is to assume time will never travel and store the latest computed date right? If you've seen 2001, it's never going to be 1999 again, so it must be 2019. I understand that will require either flash or battery backed RAM, etc to keep this stored, but seems relatively trivial in most applications... (side effect would be that if the backup battery is dead or all batteries are disconnected, you would revert to 1999)