Beware of Expiration!

The exchange deadline for the 4th Anniversary Eve Festival commemorative medal is less than a week away. Users who haven't exchanged yet might want to do so soon. Since these are permanent characters, you could wait until the last minute to exchange, but there's a risk of forgetting, so please be careful. If you don't plan on pulling any gacha, it's probably best to exchange now. As a guideline for what to exchange, first, if there's a character you like and want, you should prioritize getting them. Next would be units that you're lacking in terms of combat power (e.g., exchanging for Lulu because you lack a healer). Other than that, if you don't have characters needed to unlock premium dungeons, exchanging for the corresponding character is a good idea (e.g., exchanging for Okyu to unlock the Limit Break dungeon). Lastly, exchange for characters you don't own. Exchanging for awakening purposes isn't highly recommended as it can be substituted with Bibi Medals, but if you have no other characters to exchange for, that's also fine. By the way, as you can see in the image, I exchanged for 'Christmas Likliff', whom I didn't own and seemed useful for my team.