Harsh conditions or long exertions do not easily tire you.

Benefit: You gain a +4 bonus on the following checks and saves: Swim checks made to resist nonlethal damage from exhaustion; Constitution checks made to continue running; Constitution checks made to avoid nonlethal damage from a forced march; Constitution checks made to hold your breath; Constitution checks made to avoid nonlethal damage from starvation or thirst; Fortitude saves made to avoid nonlethal damage from hot or cold environments; and Fortitude saves made to resist damage from suffocation.

You may sleep in light or medium armor without becoming fatigued.

Normal: A character without this feat who sleeps in medium or heavier armor is fatigued the next day.

Endzeitgeist Says: Sleeping in Medium Armor without becoming fatigued is great while in the field, but make sure that your class does not already grant you this feat. Endurance is pretty situational, and while my group uses it a lot, other groups consider it useless. Ask your GM if you'll be using checks for long runs, forced marches, etc. to make sure if in doubt.