The document discusses how people underestimate the limited amount of time they have left in their lives. It notes that after daily activities like work, sleep, commute, and media consumption, only about 30% of a person's remaining time is left for friends, family, relaxation and hobbies. However, small reductions in activities like commuting, watching media and using email/news could gain back thousands of hours to pursue meaningful goals. An online calculator is provided to help people assess how much lifetime they have remaining.