My cats have never gone outside and they're fine ‍

Cat rescues have cats that are used to staying inside all the time.

This one is at the sit. Its about about ten feet long, 7 feet high. The cats get in & out through the wall cat flap. Its made out of 100mm square reo covered with chicken wire & shade cloth to keep the snakes out.

As someone who just acquired a cat that was hit by a car, I have a firm opinion that cats do not belong outside. Personally, if I had my own home or even a deck or patio I would build a catio enclosure for my babies. You could probably build or have someone build something for a reasonable cost and I've seen a number of outdoor enclosures for cats that are commercially available. If I find a link, I'll post it here for you. That being said, indoor cats are perfectly happy provided they have enough stimulation- toys, hiding places and perches, and, if possible, a kitty companion.

My cats are indoor only. Too much danger outdoors. [vetmed.ucdavis.edu]

Not sure an enclosure will work unless it has a roof or some type of cover, like a cage.

I second the first comment. Cats can live excellent lives without going outside. No diseases, no fight injuries, no getting stranded in trees. They also tend to live longer.

My girls are totally indoor kitties, & we own our own home. I had too many kitties killed outside that I just stopped letting any out. My current girls have never been outside other than in the carrier to bring them home from the shelter, or to see the vet.