Board Thread:Questions and Answers/@comment-75.175.68.74-20150623044747/@comment-24930713-20150623050046

No idea, the guidebooks give a vague idea of how often they go, but not how long they're gone. If we take all Attack on Titan media into consideration, that includes the spinoffs, then it seems to vary between one and a couple of days. It's likely they just come back after running into major problems.