Either one large or two. Two are probably more common, but one will look less busy.

We are doing 1 mirror. We have a 36" trough sink with 2 faucets. 1 long light as well.

I have one very large framed with the 2sink vanity and one smaller centered with the single sink vanities .

The pics posted above look pretty top heavy to me, so if one mirror, I'd go frameless or very slim frame, with sconces in mirror.

In fact, that's what's done in upscale houses in my area.

I'd do 2. I have one large one and it's a pain to clean.

We just replaced our large single mirror with two smaller mirrors.

I'd do too, it leaves room for the wall to show and creates a cozier feeling.

Try to put your lights on the sides and between the mirrors rather than across the top. The light for shaving or make up is SO much better. Also, plan out your spacing before installing anything. There have been threads where people discovered after installing sinks that the lights wouldn't fit, or vice versa.

Good luck!

I prefer one big mirror.