What is endurance used for in Fallout Shelter? The storage room says it uses Endurance, but what does that mean? It doesn't produce anything so what is the advantage or putting a dweller in there?
Endurance: Dwellers with high endurance can withstand a lot of punishment, and are best suited for exploring the wasteland or for manning Nuka-Cola production plants.
As few players have brought this up, the endurance is the power of the person to RESIST againts damage, when exploring the waste land he will take less radiation and damage.
Endurance increases the max HP gained each time a dweller levels up. This means if you level up a dweller that does not yet have max endurance you are permanently reducing the potential max HP of that dweller. Even though special over 10 isn't visible in the display it still has an effect so you also want the best endurance gear you can find.
Endurance is also used in the Nuka-Cola plants (which replace all other food and water buildings). If you had the foresight to train all your food and water workers for endurance early you can have some of them make Nuka-Cola and send the rest into the wasteland. If you didn't train them in endurance then you should still send them all into the wasteland... but then "forget" to call them back.
The formula is
MaxHitPoints += (BaseEndurance + OutfitEndurance) * 0.5 + 2.5;
I haven't directly tested this formula but it fits with my experience.