Have you chosen a brand that you like? I plan to purchase Electric Mirror LED lighted mirrors (this is a splurge). I am considering 42x42" or 42"H x 36" wide for a 52 to 54" wide vanity. I think they have mirrors that are even wider than 42"

Edited to add:

General recommendations for a mirror width are as follows:

- Same width as vanity

- 70-80% of the vanity width

- 4 inches shorter than the vanity width