Here is my take. When you experience something new, your brain works overtime to learn new things. Thats why in a familiar setting time flies by. I guess thats

Here is my take. When you experience something new, your brain works overtime to learn new things. Thats why in a familiar setting time flies by. I guess thats why some people are adventure seeker and travelers. At old age most of the things become routine. Here it is argued that the whole life of a person is counted. I simply think, life is divided in various threads. You do something new and a new thread is created. Its along a single thread that you may measure your perception of longevity. If you do something routine then it seems to be fast to you as it becomes routine. Also I remember a link on HN that explained how time virtually stopped for Near Death Experiences.