I read a true book about an American Priest who became an exorcist for his diocese, and his “internship” under an exorcist in Rome. This guy had a waiting room full of people he regularly treated. All had been long since vetted, and a few had been seeing the exorcist for over 2 years or more. So one a day would be small potatoes for this Priest. [though he did take a day off now and then.]