Most Corporate Show electricians with whom I've worked use yellow e-tape to denote spare circuits, unassigned mults, and "active hanging spare" fixtures. Where the convention started, I have no idea; but it's easy to identify and troubleshoot....To avoid confusion as to which lights have and have not been focused, I put little tabs of folded orange spike tape on all my over-the-stage lights. As they are focused, pull the orange tabs. Why no one thought to do this before I joined the staff, I have no idea. We used to have problems with a light getting focused for one piece in February, then refocused for another piece in April. That doesn't happen anymore.