We just had our vanity sconce replaced today. We bought a pretty, 3 light sconce with frosted glass covers for the bulbs hanging down. We need a new mirror as well. It's a small bathroom, so we were thinking we should make room for a big mirror to make the space seem larger - something like 30 x 38 for the mirror. So the question was how high up to hang the sconce. The mounting bar (or whatever it's called) is quite a bit higher than where the lights hang down to, and we figured the mirror has to start below that... but now it's so high that the mounting part is almost up to the ceiling! It's looking a bit weird to me, but I don't have a mirror in place yet, so I don't know. How is one supposed to figure this out? I can't do it by seeing my reflection and shadows since I have no mirror yet...

Thank you!

I wouldn't set any boxes or wires until you get the mirror.
There is NO standard height for vanity lights for the exact reasons you are describing.

Good point... too late, it's mounted - but we could still have it moved. There's all kinds of dry wall patching that needs to be done. To add to the complexity, the ceiling is arched, so it's lower by the walls and higher in the middle. That makes the sconce look close to the ceiling even though it's not that close from the highest point. This is hard to figure out. I don't even know how big the mirror should be... how much of the wall it should cover...