How many levels do you think a level 39 could gain with a xp pot with 25 quest to turn in along with headless horseman dungeon bonus xp, and random dungeon bonus xp.
just hypothetical math, but assuming your toon hav 300% xp buff with flask and the other buffs, you'd get near 2 million xp in 1 hour, from lvl 39 the toon could reach lvl 55-60
