Yes, your vanity does need vanity lights. Vanity lights are very important especially in small areas like the bathroom. The benefits of having a vanity light include:
Depending on where you place your vanity light will determine how high it should be.
If you choose to have the vanity light above the mirror, then the vanity light should be placed around 75 to 80 inches from the floor.
If the vanity light is placed on the side of the mirror, then the light should be around 60 to 70 inches from the floor.
Remember to consult with an electrician to make sure the placement of the vanity light is safe and meets safety regulations.