I currently do not require a minimum stay, but charge a premium for this. I’d like to be able to offer a discount for second and subsequent nights, but can’t work out how to do this.
There are more complicated ways to do this, but what works best for me is to simply set a reasonable nightly rate and then add a cleaning fee.
Because the cleaning fee is per booking (not per night), it automatically makes short stays more expensive and spreads out over more nights as the stay gets longer.
The guest only sees the total cost, so they make an informed decision based on the total price for the dates they selected.