NUMBERS Number each circuit, bearing in mind that depending on how (and when) your house was wired, individual rooms may have more than one circuit—and in older homes, one circuit may show up in multiple rooms.
NAMES Go with location (“right rear bedroom”) rather than current use—a label like “Jack’s room” or even “office” isn’t helpful to non-family members. For bonus points, post a simple floor plan of your home on the box’s door.
COLORS Add a hue or two to highlight anything important or unusual (on the box at left, blue denotes unassigned circuits). Old houses often have “mystery breakers,” which can be left off—just be sure you aren’t accidentally shutting off smoke detectors.