Well Rested

A status effect that grants the player a +10% experience boost for 12 hours after sleeping. The Broken Steel Perk, Deep Sleep, grants this status effect after sleeping in any bed.

The  effect is obtained by sleeping in a bed you own (i.e. in your Megaton house, your Tenpenny Suite, a rented bed, or a cot in Kenny's Cave).

The effect lasts for twelve hours from the time you awake, regardless of how long you sleep. If you sleep in any bed it will cancel the effect but if it is an owned bed it will return immediatly.