For me each shooting session is done with purpose and that changes the number of arrows released. I set up my own bows and I shoot a lot more arrows getting them dialed, sometimes 100 or so. I am breaking in the bow and don't care how well they shoot or group. The initial set up gets me close. Each arrow is still shot with form as first and that never changes, but I'll shoot a lot to get things to settle then shoot less the next time.
I don't set an arrow count. If I shoot 20 great arrows I'll keep shooting another 20 (or a 100) if I can shoot them great. Form takes a lot of practice. I have heard some archery coaches talk about shooting 1000 arrows in a day. For me this is not possible, but the more arrows I can shoot in a session with the same form and consistency the more likely I am training the mind and muscles into habit. I stop shooting when the form breaks down. Unless I'm building endurance and muscle. I often don't care where the arrow goes as long as the form is good, and the arrow flies well. If the form is good and the arrow flies off then I can start to narrow down the problem. Good arrow flight and good form is the focus of my shooting sessions. The goal is to get consistent small groups then I can sight in to make the groups hit the point of aim.
When it's hunting season I think the first arrow of each session is the most important for me as it mimics the one arrow on an animal. Those sessions may come once a week or once every few days so that first arrow stone cold with no practice tells me a lot about how well I have muscle memoried my form. I don't stop with one shot. I will keep shooting again focusing on form.
Maybe that's too serious for some, but I enjoy the challenge of it. To each his own, I don't really think there is like a wrong way to practice per se.
