Wait til you have a legacy system and a newer system and need to, among other things: - Implement redirects from the old login screen to the new one - Keep ses

Wait til you have a legacy system and a newer system and need to, among other things: - Implement redirects from the old login screen to the new one - Keep sessions in sync - Make sure all internal and external users know how to clear cookies - Remind everyone to update bookmarks on all devices - Troubleshoot edge cases