Q. Why should we chant fixed number of rounds, even though in scripture it is not mentioned?
A. It is not ‘fixed’ but ‘minimum’ rounds. Minimum is 16. You can choose to chant 32 or 64 or even more.
We are practicing sadhana bhakti. This is devotional service in practice. So, these are the techniques recommended by acharyas to regulate our mind’s activities and engage them in thinking of Krishna in a systematic way.
“A man engaged in devotional service rids himself of both good and bad reactions even in this life. Therefore, we should strive for yoga, which is the art of all work”-(2.50).Yoga is an art. When you are learning any art, you must be systematic and disciplined, and you will need to bench mark your progress. So also in sadhana Bhakti, we have some systems implemented by acharyas which will help us in making gradual progress. The question is of disciplining ourselves and sincerity.