Having a beholder eye(s) transplanted onto a character are grounds for so much abuse. A novel in the Waterdeep Nobles series has such a character, who makes use of a "Cause Serious Wounds" effect with a replaced eye. It is noticed that this character suffers an increasing amount of life energy loss with repeated use of this eye power. How often can a character make use of "Eye powers" in a single day? Need it be a set amount or can a loss of hit points be assigned to various effects? A Dungeon Master is of course free to set any number of restrictions on the use of Game-breaking "infinite wand powers" a character has, but it would be nice to have a set amount since the company touched on the subject within their book.