The Flexible Search tool offers four stay-length options, and you can choose which of them your guests see.
To change this, open the Flexible Search settings panel in the Toolkit Hub and select the stay-length options you want to show. If you run short stays, for example, you can show only "Weekend stay" and "1 week" so the choices match how your guests actually book.
The same panel also controls how many months ahead the month picker offers.