Board Thread:General Discussion/@comment-33409689-20171111041729/@comment-30514476-20171111051217

Events don't repeat, rather you will get new events with new rooms and new access passes required to open them. For expample: Lair was Halloween 2017, Gloomy House was Halloween 2016. Green potions are only used for the Lair.

When the special events expire, the event rooms will be permanently added to the game thus becoming available to those who missed the event. Some of the event rooms remain Premium locations that need access keys (like the green potion) to play, others become regular locations that don't require any access keys. You can check out the list of all the locations here.