One chanting of Krsna is sufficient

Now you can try to understand how powerful is this pure chanting of Hare Krsna mantra.Offenseless chanting of Hare Krsna mantra means you remain liberated always. Offenseless chanting, once chanting is sufficient. But because we are not offenseless, therefore we have to make a regulated program that we must chant Hare Krsna so many times. Otherwise one chanting of Krsna is sufficient to make you liberated, one chant, "Krsna," "Rama," once, that's all, sufficient. Just like this Ajamila. Once he chanted Narayana. He became immediately liberated because he was offenseless.

But because we cannot do that, therefore we have to make a prescription. Just like a child who cannot write very good hand. He is asked that "You write so many pages." By writing, writing, writing, writing, writing, he writes good hand. So we should not neglect. Chanting,chanting, chanting... An other... This is one side. Another side is when you become liberated the chanting will give you transcendental pleasure so that you cannot cease. You cannot cease chanting. That is another side. That is liberated stage, just like Rupa Gosvami, Haridasa Thakura. You cannot imitate Haridasa Thakura but you must make a prescribed form that "I must chant so many times." That is for conditioned soul. When you are liberated, then there is no need of giving you direction. You'll feel transcendental pleasure by chanting. You cannot cease.

(Srimad-Bhagavatam 6.2.11 -- January 16,1971, Allahabad)