More than a century back Swami Vivekananda expounded that we all have to die and if we become aware of this reality in our daily thoughts, the result would be that we will become a better person, our productivity would increase in terms of quality and quantity.

Conversations with Swami Vivekananda

Once a group of college students visited Swami Vivekananda and he asked them this question: ?Which truth is the grandest of all truths in life?? and this was his answer:

Look here-we shall all die! Bear this in mind always, and then the spirit within will wake up. Then only meanness will vanish from you, practicality in work will come, you will get new vigor in body and mind, and those who come in contact with you will also feel that they have really got something uplifting from you.⁽¹⁾

Wouldn't thinking of death always make us depressed and take away all zest for life? It would in the short term, the real benefits take a while to surface. Swamiji agrees:

Quite so. At first, the heart will break down, and despondency and gloomy thoughts will occupy your mind. But persist, let days pass like that?and then? Then you will see that new strength has come into the heart, that the constant thought of death is giving you a new life, and is making you more and more thoughtful by bringing every moment before your mind's eye the truth of the saying, "Vanity of vanities, all is vanity." Wait! Let days, months, years pass, and you will feel that the spirit within is waking up with the strength of a lion, that the little power within has transformed itself into a mighty power! Think of death always and realize the truth of every word I say.⁽²⁾

1. Complete Works of Swami Vivekananda, 8 vols. (Calcutta: Advaita Ashrama), 5 (1973): 329.
2. CW, 5 (1973).329-30
Readings

In March 2009 and again in May 2010, Swami Tyagananda of the Ramakrishna Vedanta Society of MA, spoke on the subject titled "The Last Day". In his Swami Tyagananda spoke of how treating each day as potentially our last one, without being obsessed with the thought, can enrich our lives.
Listen to Complete talk (47 minutes, mp3 format).

In his 2005 commencement address at Stanford University, Steve Jobs also spoke on how the thought of dying one day made him think big and put life in proper perspective, expecially with his illness. Read full text on Stanford University's web site.

Excerpt:

My third story is about death.
When I was 17, I read a quote that went something like: "If you live each day as if it was your last, someday you'll most certainly be right." It made an impression on me, and since then, for the past 33 years, I have looked in the mirror every morning and asked myself: "If today were the last day of my life, would I want to do what I am about to do today?" And whenever the answer has been "No" for too many days in a row, I know I need to change something.

Remembering that I'll be dead soon is the most important tool I've ever encountered to help me make the big choices in life. Because almost everything, all external expectations, all pride, all fear of embarrassment or failure - these things just fall away in the face of death, leaving only what is truly important. Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart.
Steve Jobs