Reluctant Indoor Cat Owner.
The Youngest Cat - Poor Boy!
These are interesting questions.
I am on the whole a believer that cats are healthier if allowed access to The Great Outdoors, being allowed to bask in the sun, eat grass, catch insects, climb trees, sharpen their claws where they like etc. I have always kept my cats inside at night in the hope that the wildlife would be less depleted that way and my pets would be safe, though cats catch wildlife in daylight hours, too. I've rescued birds and large lizards from my cats many times in broad daylight.
Now I live in a 'gated' community where my cats have to be totally controlled, or I can't have them. So I have become a reluctant Indoor Cat Owner. My cats are 14 and 17 years old and I do not want to be without them. They are my pets, and they are well-looked after.
The oldest one is blind now (well, he can see light and dark I think - he has cataracts). He obviously cannot be allowed free range anyway for safety's sake. He has stopped jumping though which means an ordinary fence can keep him in, so I let him out in the (minuscule) yard with me off and on. He stays by me most of the time (I am home all the time myself). So he is happy, I think.
I do feel sorry for my younger cat who loves a good wild romp over the fences and into the trees. He is more restrained indoors, thankfully, but he misses being able to go outside freely, I can tell. I play with him indoors, making silly toys and encouraging him to chase them and attack them and so on. I sometimes let him out inside a cage, where he can access the grass and the sun, but it really is a constrained life for him.
I feed them both raw chicken necks every second day and that seems to keep the hair balls down.
If I had my 'druthers my younger cat would be able to come and go at will, except I would still keep him inside at night so I know he's not killing, being killed or annoying the neighbours somehow.
So I guess my answer is that it depends on both the cat and the owner's needs, whether they are outside or inside pets :)