Got a question about composting

Been watching videos about composting and it seems everyone has a bin or two or three , and they fill them with kitchen scraps, sprinkle them with water every few days, and turn them for aeriation.

OK, that is simple enough. However, if you have a continuous flow of kitchen scraps, how do you manage the composting bin ? Do you throw stuff in it daily ? If so, the stuff will not be at the same stage of decay. Some will be still visible food scraps (like banana or orange peels, or lettuce leaves), while older stuff have already turned into brown fertilizer. There will not be a "DONE date".

So, what is the trick ?
Thanks