As this is the Swyama Siddha Hanuman Mantra it does not have being chanted for a set amount of Mantra Repetitions for having the ability to use it. Unique worship and rituals and regulations relating to way, sitting mat, and counting rosary usually are not advisable for chanting this Hanuman https://www.youtube.com/watch?v=ufkmD95y7fE&t=32s