Expertise

Overview

 * Expertise is the primary attribute of Rangers, and thus only accessible to them.
 * Expertise reduces the energy costs of all non-spell skills from any profession at a rate of 4% per point. This is contrary to the in-game description which claims it only applies to "Attack skills, Preparations and Traps".
 * See also the list of skills having Expertise as their main attribute.

Skill Cost Modification By Expertise
Same data displayed differently to show its pattern of "-1 pyramids":