Duvet and cover
A duvet in a removable cover is quick to make up and looks generous. Only the cover is washed between guests, but changing covers takes practice.
Top sheet and blanket
A flat top sheet with a blanket or coverlet is the traditional set-up. The sheet is washed every stay; the blanket less often.
Choosing
Think about housekeeping time per room, laundry capacity and the climate. Many operators use a duvet with a third sheet as a middle ground.