I am someone who has been highly uncomfortable with caged birds. Since I am very connected to animals I could sense when I got cockatiels and parrots that they wanted to be free to fly and explore. I also do not clip my birds so they can enjoy flying, one of the wonderful thing about being a bird. I have lived with birds for thirteen years in one room cottages and now a bigger house where I can give them a “bird room”. I decided after a few months of watching caged birds mine would be free. I trained my cat and she did wonderful and never killed a bird indoor or outdoor in spite of the fact she killed numerous birds before (I credit Penelope Smith interspecies communication training for being able to do this). So it takes some focused work.
I have ran into some issues. I have lost two cockatiels who got fed up with the room and wanted more freedom and managed over time to escape when I opened the door. In both cases they really worked hard on a strategy. Most of my other birds were very happy with my current structure, an outdoor aviary connected to the room and indoor space they can fly in anytime. It does require more cleaning as they decide they love your office chair more than their perch but for me a small price to pay to see them happy. I use tarp for the areas they like to hang out, and I hide objects that are dangerous in drawers. Sometimes I do find out the hard way. My parrots love remote controls, and paper of all kinds, and pen but they have survived in spite of destroying some of these. I have lost a computer keyboard when my conure decided to pop up all the keys and I realized I had no idea which keys went where? So, some mischief happens. I call them “projects”. Funny how parrots much prefer using your stuff as toys and they do not touch the things you buy as parrot toys. So be prepared for some “projects”.
I am sure that each parrot has its own preferences and if some parrots eat electrical wiring or other dangerous items it is not a good idea to let them free and unsupervised… I also would say that since I got a friend for my conure (a pionus), he is a much happier bird and the destruction is much more limited because they spend time grooming and interacting opposed to being alone. I guess it helps if you cannot give a lot of attention to your parrot to get a friend.