Create a pricing rule for a listing or a listing group.
From the "Rule Type," drop-down menu choose "The Day After a Reservation," or "The Day Before a Reservation"
Under Options choose "Set Availability"
Under Availability choose "Blocked."
To make sure that you never have a check-in or check-out on the same day you will need to create two rules. One to block the day before a reservation and one to block the day after a reservation.