On average, a professional can sand between 15 to 20 square metres per day. However, the exact duration varies based on several factors, including the condition of the floor, the type of wood, the layout of the room, and the equipment being used. For example, heavily damaged or uneven floors will take longer to prepare and sand properly. Tight spaces, corners, and staircases can also slow down the process. A simple room in good condition might be done in a day, while more complex jobs could take several days.