A Zen monk does not completely fill his days with tasks. In other words, he is not stressed out by the amount of work he has ahead of him each day.
He is not lazy, he rises early and has a day filled with work. He has a certain number of things he wants to do this day and no more. By doing less, he can concentrate and do the tasks more slowly. His goal is to be deliberate with his tasks, not to do as much as he can in the shortest time.
He leaves space between tasks in case one task takes longer than he planned. That way, he doesn’t struggle with an overcrowded schedule.
And why does he wish to be deliberate and mindful with his tasks? The answer is to free his restless mind from activity. By experiencing moments of restfulness in his mind, he escapes time. He is in a timeless, formless place conserving energy by not thinking. This frees up his energy to create other things. Attention to his ego wastes the greatest amount of energy and he realizes this.