Most guests book two nights. The ones who book four tend to come back.
Marrakech rewards slowness. The first day is noise and colour; by the third, you know the alley to the bakery and the man who sells oranges at the corner.
Unpack properly. Put your phone in the drawer. Take the hammam in the afternoon, not as an errand but as the main event.
And leave one day with nothing planned. It is usually the one you remember.