We have two possibilities for adding a catio to the rear of our house, enclosing an existing cat flap in the wall--one would be on a small space of wall between two windows (roughly 5 ft wide x 4 ft deep x 7 ft high), and the other would be larger (about 10 ft wide x 4 ft x 7 ft), which would enclose not only the cat flap, but also the French doors that are currently the only way into our back garden, so it would act more like a mini screened porch. However, if we did that, the only route for us, the kids, the dog, etc. into the back yard would be through the catio.
I know the larger size is preferable in terms of being able to provide more enrichment and variety for the cat, but it seems there are potential downsides in terms of allowing the cat chances to bolt when the catio door is opened for us/dog to go through, and maybe durability issues as the catio door would get a lot more regular use than in the small version. A potential upside is that we could put insect screening on the catio and leave the french doors open in warm weather without bugs getting in (we're in the UK, so it's not like a Florida problem, but would still be nice), although that means the dog would also have free access to the catio in that situation, which has the potential for annoying the cat (although he would have shelves and things to get up high.) The smaller one has the benefit of the cat having his entirely own space. We've never had a catio of any sort before, so any help with those who have lived experience of the pros and cons of either of these setups, I'd be happy to hear from you!