I have 2 cats, i would call them seasonal indoor/outdoor cats.
We live in a apartment, its on the first floor and the balcony connects to a fenced in(by brick wall) courtyard thats probably 100'x150' and has no outside access, just to the first floor apartments on the inside edge of the building. In the spring/summer while we are home the cats are allowed to freely roam in or outside. in the winter they are inside only, while we are not home they are inside only. We never have problems getting them to come in they are oddly well behaved for cats. They could for sure get over the brick wall they just choose not to.
Both are very scared of cars and run from them, and both are very territorial and protect what they think is "their" courtyard and generally just patrol the perimeter and visit the first floor neibour friends when they are outside. I have never seen either more than 200' from my balcony, and both come when called which is odd, they both know their names.
So i guess we have it good compared to most indoor/outdoor situations.
They would be so sad if i didnt let them outside and they are so well behaved while outside i dont see the point in not letting them out.
And we have had one for 9 years and the other for 5, so this situation has been working fine for almost a decade.
The older female Mona is a bird killer, there are 6 small 15' tall trees in the courtyard, she is a tortie colored cat so blends in perfect with the tree trunk, she will climb the tree high up and sit still for hours, when a bird lands on a branch below her she will pounce down onto it so even if it jumps to take off its jumping closer to her making it easier for her, shes no dummy and she rarely misses and shes 11 years old now so getting up there for a cat.