Mirrors are pretty easy to pick, the easiest way to pick the right mirror will be depending on the vanity, so we always want to get the vanity in place first.

And the reason for it is, if we don't know the style or the size of the vanity, it will be hard to determine which mirror will fit us better.

What we want to remember is one thing: when we have a wall next to the vanity (exactly right\left to the vanity), we will want the mirror to be 2"-5" shorter than the vanity size, so it will not get "stuck" on the wall.

Unless it will be a frameless mirror, and that is usually made by our glass-guy, since it's custom.

Also, you want to make a decision if you have a 2 sink vanity if you rather go with 2 mirrors, one for each, or a long one for both.