Time isn't precious at all, because it is an illusion. What you perceive as precious is not time but the one point that is out of time: the Now. That is precious indeed. The more you are focused on time—past and future—the more you miss the Now, the most precious thing there is.
The Power of Now: A Guide to Spiritual Enlightenment (ed. New World Library, 2010) - ISBN: 9781577313113