When I leave a map (like Ancient Pyramid, Fetid Pool, Tidal Island...) through a town portal, entrance, or teleporter and immediately return to it, the map stays explored.
But, if I don't return for about half an hour in singleplayer (without a party), I have to start over with exploring the map.
How long can I stay outside a map without losing my exploration progress?
You can stay between 8 and 15 minutes outside an instance before it reset:
Poe wiki :
"All areas in Path of Exile are instanced. When you enter an area, a new instance is created. Once you leave the area, the instance will remain in its current state for 15 minutes for main areas - if 15 minutes passes with no players entering the instance, it will be closed. Entering the same area again will create a new instance with a new randomly generated map. Areas without side areas attached (any area with two or less exits) has a shorter timer, and will only last 8 minutes while empty."
In addition, you can open the Instance Manager menu with 'CTRL + Left Click' on an entrance (or portal) that will show you exactly the time left after the reset of the instance.
It looks like this (patch 2.2.0):
It is mainly use to reset manually an instance for farming a specific area.
Between 8 to 15 minutes, if they are empty. They won't reset when there is a player in the instance, and the timer resets when a player entered the instance.
I can also add an in-game screenshot from the tips in the loadingscreen if needed.
Maps are Auto resetting after 15min. Have a look here, for enter the same instance.
