Special attention is paid to the quarterdeck's cleanliness and physical appearance. Those standing watch on the quarterdeck must be in the uniform of the day and present a smart appearance at all times. Personnel not in the uniform of the day generally avoid crossing the quarterdeck unless their work requires it. On ships with a well-defined quarterdeck area, uniformed personnel should salute when they enter it. Smoking and recreational activities are prohibited on the quarterdeck unless specially authorised by the commanding officer.