You can use a light fixture that is as large as the space it will go in minus a few inches, but do try to get something that looks proportional to the space. Same goes for the mirror. I don't know why people are going toward the framed mirror look unless it's just that keeping the builder-grade cut mirrors isn't something most people are inclined to do in a renovation due to any damage that may have occurred over years of use. Take a look at Toto sinks. They have some nice finishes. Read reviews of any particular sink you might select, as some wear better than others. Wayfair and Amazon are good places to find sink reviews.

The bathroom is 12 ft long on one side only because a hall closet takes up about 4 ft on the other side. The light will only shine on the 4 ft countertop, shower, and toilet, so I am worrying about the room being bright enough since there is an 8 ft wall with no lighting. There is a heater/vent/nightlight in the ceiling, but it is pretty dim.

We have Toto toilets, but I have not seen Toto sinks. I will look for them. Thanks.

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I have noticed that a lot of people are getting smaller framed mirrors, instead of the wall-to-wall builder grade mirrors. When doing that, the framed mirror is usually about the same width as the vanity and at least 6 inches above it, as well as at least 6 inches from the lights.

Here is some additional information:

FrameMyMirror, thank you! That is exactly what I was looking for. You wouldn't happen to have the same info for how to choose bathroom lights, would you?