As the kids get older in most countries they will need 2 rooms. Other than costing twice as much it is much nicer to have the extra beds and bathrooms. When our kids were younger we got connecitng rooms and kept the door open between them, making sure the exterior door to their room was deadbolted. Now that they are tween/teen age we don't even care if they are conencting as long as they are within a few doors of us.