A combination vanity unit combines a single vanity with a matching or complementary countertop so that 2 people can use the vanity at once. This makes it easier for friends and family to share the cost of the vanity, without burdening a single person. Usually, this type of vanity also has a complimentary decorative theme that matches other adjoining fixtures in the bathroom. Because the vanity and the matching countertop are adjacent to each other, they don’t interfere with each other’s functionality.