The animation ends with what looks like an aerial view of a city. The whole city represents a lifetime. Each transverse street represents a year, each building a week, and each yellow block or "apartment" is a day. As we survey a lifespan from this novel perpective, we might think that there are many days or very few. Of course, although "absolute" hours and days can be viewed in this way, it is a common experience that time speeds up with age. If this graphic were a subjective view, then the later years in our city block would have progressively lower buildings, as the hours compressed to reflect our subjective experience of time passing faster! An interesting question is "At what age might we have subjectively experienced half a lifetime?" Could it happen in early childhood, even for an 80 year lifetime? Carpe Diem!
Our life expectancy, how long we might expect to live, depends on many factors, such as when and where in we were born and the genetic hand we were dealt. Then there are diseases and trauma to consider. Actuarial studies might be concerned with the risks and statistics that apply when calculating premiums for life insurance. Wikipedia has a great article on life expectancy.