Answer
It all depends on one's mindset.
A devotee can always find reasons to justify delaying chanting. But if you complete your rounds late in the evening, you should honestly ask yourself whether that time could have been used more effectively in the morning.
When this temple was being built and we were living in temporary sheds for nearly ten years, everyone followed a strict standard: before honoring prasadam, everyone completed sixteen rounds. This was carefully monitored.
Why was it so important?
Because chanting sixteen rounds is your daily yajna (sacrifice). During that time you completely dedicate your mind to Krishna.
Think of every Hare Krishna maha-mantra as one offering of ghee into a sacred fire. Every bead on the japa mala is another sacred offering.
Complete your prescribed sixteen rounds with determination every morning.
The spiritual strength you gain for the rest of the day is extraordinary.
If you truly want to serve the Lord effectively, first nourish your own consciousness. The clarity, intelligence, and inspiration you receive from Krishna while chanting will guide all your services throughout the day.
Do not reverse the process by spending the entire day in service and postponing your chanting until night.
As far as possible, devotees should complete their sixteen rounds in the morning. If a pujari cannot do so because of temple duties, he should at least complete them before lunch. Every devotee should consciously make time for this essential practice.
One should feel that the day is incomplete if one has not performed this daily yajna of sixteen attentive rounds.
Make it your daily target.
When you consistently complete your chanting early, your entire spiritual life becomes protected. Day after day, Krishna gives protection, guidance, and clarity.
As the years pass—five, ten, twenty, even forty years—you will continue progressing happily and steadily in Srila Prabhupada's movement.
The most important foundation of devotional life is to chant sixteen attentive rounds every day.