We have always made appointments, but on the last trip showed up about half an hour early and there was no one there, so we got it done early. We were there in January, so it was quieter, but we literally had the place to ourselves when we arrived. Some people arrived after us for "walk-in" and they were seen right away.
Also, the First Haircuts for us only took like 5 minutes. So they can usually squeeze in you pretty quick.