Dennis Genpo Merzel writes in The Path of the Human Being: Zen Teachings on the Bodhisattva Way:

Zen Buddhism focuses on the Buddha’s teachings about direct realization. Buddha used his wisdom to come up with skillful means to help us go about liberating ourselves. Zazen is the most direct path, but because we all have other obligations to fulfill, the Buddha taught how we can maximize each sitting: practice awareness every moment of the day. In a way, it is a waste of time to sit on the cushion if we are not also practicing being attentive, awake, and conscious the rest of the day. By practicing awareness throughout the day, our zazen and our daily life will reap the rewards.