This game is heavily focused on storytelling, so end the game when it feels right for your group. If playing with a DM, the DM can decide when a good stopping place would be. If no DM, players should end when it feels right, but keep in mind playing for a long time can get boring or tiring. You have your own Hanukkah celebrations to go save!
If you need a mechanic to help you end the game, consider 5 failed Encounters as your ending point (or a few more or fewer, if that feels right to you). When you hit the maximum, play out one final scene so you all can decide how the story ends.