This is a wonderful devotion for May from Catholic YouTuber Journey Deeper. If 1 Hail Mary is so powerful, imagine how powerful 1000 Hail Marys must be. It must be like a complete rout of Satan and his devils forcing them back to hell. St. Padre Pio is reported to have prayed 150 to 200 decades during the day! This counts as 100 decades. It includes all 20 mysteries. It takes roughly 5 1/2 hours.