For sanitary and security reasons, I build this big fence of 700 square meters, so the cats can enjoy the garden in total security (from cars, from neighbour cats). The fence is equiped with electricity on its top (and outside), to avoid any escape or neighbour cats coming to annoy them. My cats have access to their garden from the house through a flap, so they can, during the day, go in and out as they wish, and that makes them very happy, while they are securised.