Gold for xp

In Tomb of the Serpent Kings, you don't earn XP from milestones, or defeating monsters, or completing quests.

You get it from getting gold from dungeons and bringing it back to town to spend it. You get gold for getting XP, otherwise known as "gold for xp."

Games that use gold-for-xp encourage exploration and creative problem solving over games with other kinds of experience gain, as the way you achieve the task doesn't matter, as long as you delve deep and explore to find the gold and then get it out.