What lessons do you learn by observing someone’s death?
I learned the following lessons after observing the death of my grandparents:
1. Everything in this material world is temporary and full of pain.
2. Death can come at any moment and take away all our material possessions in a second, but whatever devotional service we have rendered is our eternal asset. I realized that I am going to die one day.
3. There is no use of becoming mad after money and hoarding things that are worthless.
4. Chant Hare Krishna and be happy serving the mission of Srila Prabhupada. 
I need to get detached from the bodily conception of life, so I can remember Krishna at the time of death. 
(Premanjana Dasa)
By observing the death of my mother-in-law, I learned that the devotees of the Lord can work miracles. On the last day of her stay in the hospital, she was in a state of terror. She began to see some “big man,” “buffalo,” and other strange things. When we brought her home, devotees comforted her by singing kirtanas, showing her beautiful pictures of Radha and Krishna, and by encouraging her to chant the holy names. After two days, she felt peaceful. She then called all of us and blessed us and said she was leaving. Soon she passed away peacefully hearing the holy names. I realized that association of Vaishnavas saved my mother-law from the hands of the Yamadutas and made her join Krishna’s party.
(Manoharini Radharani Devi Dasi, Chennai)
My mother used to often visit the ISKCON temple in Juhu, Mumbai, and was chanting 16 rounds of japa daily. In December 2010, she started reading Srimad-Bhagavatam and had almost finished reading it. Her death was one of the most peaceful deaths I have ever witnessed. Just one hour before her passing away, I had talked to her on the phone for 10 minutes, and I never got an indication that she was about to leave. She had gone to take a short rest, and in her sleep, she passed away.
Lord Krishna has taken her so peacefully without giving much trouble to her. Such is the mercy of the Krishna He surely takes care of His devotees at the time of death. 
(Rajesh Kumar Mishra, BARC, Mumbai)
My mother died of Vasculitis at the age of 59. She was a successful person and had won many awards, medals and certificates during her academic and corporate career. After her death, I realized that whatever material education one may have, it remains valid only until this body is alive. All our possessions that we value so much have no meaning after our death. Nothing, even our education, will come with us, nor will these material possessions help us at the time of death. The only thing that will really help us at the most critical time is the Lord’s holy name. 
(Madhavigopi Devi Dasi, Bangalore)
Seeing someone’s death is a wakeup call that reminds me how I am utilizing my human form of life in a spiritual way. I try to remember Lord Caitanya Mahaprabhu’s message kirtaniyah sada harih. It is my constant endeavor to devote maximum time for chanting the holy name offenselessly and also hear (sravanam) about the scriptures from pure devotees.
(C V V Bhadram, Hyderabad)
Whenever I observe the death of someone, be it a stranger or a known person, it leaves me deeply shaken. I get jolted out of my material existence to experience the absolute truth of life truth that comes mysteriously and without notice. I understand the temporary nature of life. We spend all our time in accumulating money, and maintaining family and relatives, but everything is snatched away from us in a moment. We are left all alone in our unknown journey into the next world. It reminds me of the insignificance of my minute existence in this creation.
I become more determined to get prepared so I may not forget Krishna in that defining moment because that is the only thing that I can carry along with me into the next world, and no one can snatch it away from me.
Recently, I visited a hospital where one of my relatives left his body. I saw how this person, who was so healthy and lively, was now lifeless, because the soul, the source of all consciousness, had left the body. I realized how everything in this material world is perishable. Everyone, whether rich or poor, strong or weak, has to die one day. In this unpredictable material world, death is the only event which has one hundred percent probability. This is the law of nature, and no one is an exception to this. I also realized that we should not love a person on bodily platform. The ultimate truth is that we are not the body but the sac-cid-ananda spirit soul, part and parcel of the Supreme Personality of Godhead.
(Colonel Ashok Sayanakar)
I have a dual perception of death. Death of a devotee makes me imagine how Lord Krishna is ready with all his paraphernalia waiting for His beloved child to welcome him into the spiritual world.  On the contrary, when a non-devotee dies, I worry for the soul that may have to again enter into the cycle of birth and death and continue so until he achieves love of God. In either case, death teaches me the following lessons:
1. Life is a preparation and death an examination.  The more prepared we are, the less fearful its outcome.
2. Our existence in this material world is uncertain and unstable; there is danger at every step.
3. Lord Krishna is always waiting for us to turn to him.
(Sini Sandeep Kaimal)
I had not seen anybody’s death until I saw the death of my father and father-in-law. In spite of my mature age I could not believe the horrible death experience of my dear ones. Dreaming every now and then that my father is coming back, I become mad with grief. At that time my husband took me to ISKCON Bangalore, where my son-in-law is serving. There I purchased Bhagavad-gita As It Is and read it continuously for more than eight times. During that period I had Krishna’s blessings and mercy. My spiritual eyes opened, and my physical eye never deluded me again.
(Lata Vaant Bettgeri)
When I observe the death of someone, I remember Bhagavad-gita (2.27), wherein Lord Krishna says, “One who has taken his birth is sure to die, and after death one is sure to take birth again. Therefore, in the unavoidable discharge of your duty, you should not lament.” The first lesson I learn is that birth and death are a matter of course, and mourning over the change of form is meaningless.
Man comes in this world empty-handed and goes empty-handed. His material achievements during the tenure of this life are transitory. The second lesson I learn is that one should detach oneself from transitory material entanglements, engage in spiritual pursuits and attain to Godhead in this very life.
(Rasa Purusa Dasa)
An English poet had once stated, “Don’t ask for whom the bell tolls, for it tolls for thee.” I understood that life is a preparation for the final exam of death. I need to work hard during my study term life in this material world by chanting the name of the Lord,  by remembering Him, and by serving Him and His devotees, so that at the time of death, whenever it comes, I am well prepared and can expect to get through with distinction.     
(Gautam Saha)