Here are some tips for choosing the right size LED mirror with lights: 1. Consider the vanity size: The mirror should not be wider than the vanity it's hanging above. 2. Think about height: When hanging a mirror over a vanity, it should be at least a couple of inches shorter than the height of the ceiling to avoid crowding. 3. Consider the thickness of the frame: If you're hanging a framed LED mirror, keep in mind that the frame will add thickness to the overall size of the mirror. 4. Think about function: Consider what the mirror will be used for. If it's primarily for grooming and applying makeup, choose a larger size mirror that covers the entire vanity wall. 5. Think about proportion: The mirror should be proportional to the size of the bathroom. If it's a smaller bathroom, opt for a smaller mirror. If it's a larger bathroom, a larger mirror is better. 6. Consider placement: If the mirror is hung above the sink, make sure it's centered over the sink and not too high or low. 7. Get creative: Mirrors don't have to be rectangular or square. Consider using a round or oval mirror to add visual interest to the space.