score:6
Many hotels have a card somewhere in the room that explains that in order to save the environment they will not change the bed linens every day if you are staying more than one day. This card should also say that they will change the bed linens if you put that very card on the bed so that it is clearly visible to housekeeping staff.
Here is an example card.
If you can't find such a card in the room, you can always ask the front desk what to do.