The mirror is wider than the compact vanity below it. Its illuminated outline extends across more of the wall, while the basin furniture remains a smaller element beside the door. Choosing the two widths separately gives the washing area a different balance from an equal-width pairing.
Look at the available wall above the basin as well as the furniture footprint. A broader mirror can suit a narrower unit when the surrounding doorway and cupboard allow it. Here, the washing area makes use of wall width above the basin without enlarging the vanity beneath.
