I remember reading somewhere on the internet about a person who had a decorative bowl in their house. This bowl was full of marbles. Once a week, they would take a marble out of the bowl and throw it away. Each marble was a week of their life. When they started this practice, they calculated their life expectancy and bought enough marbles for each week they were statistically expected to live. The idea is to give you the constant reminder that our time is limited, always running out, and shouldn't be wasted. The older you get, the less time you have, and the fewer marbles that are left in that bowl. If you are a typical HN reader, you likely have less than 3,000 marbles left.