the majority of the time it is hung way too high.
a good rule that I heard once is to hold the picture, mirror, clock, whatever, at eye level and then move down 3-4 inches from what you think is eye level.
some people will try to put an exact measurement on it, but that doesn't make much sense to me because people's heights vary and ceilings heights can be very different.
In galleries and museums they usually aim for around 58-60 inches (from the floor) to the center of the picture.
But what if you're 5ft tall and live in a basement apartment with 7ft ceilings?? yea, go lower.
What is important is that it relates well to the room and furniture surrounding it.
You don't want to have your art hung way above your couch, bed, or sideboard, and yet you don't really want it touching.... well maybe a sideboard or table. I do love leaning art. but never mind that for now.
A good rule of thumb is to hang things 3-4 inches above the sofa or bed, so they relate to each other and look cohesive.
A few examples:
these may look obvious, but I know so many people with what could be great spaces, but have pictures just floating around on the walls.
here are a few that got it right, in more ways than one
you know I love a good map. not so much cats. well not the cat, the fur.
but like everything else in life and the English language
there is always, always an exception to the rule!!
maybe I'll do post soon about breaking the rules with your wall art :)