A body of water that is flowing can be of great use. Whether it is a river or ocean, the movement can generate much power. Stagnant water on the other hand can harbor diseases and will be undrinkable. And throughout ones life, one can see how much money has gone through ones hand.
To catch how much one has made in their lifetime, one merely has to add their gross income for every year. Next, one can see how much one has captured or saved by looking into ones savings account. Finally, one must see how much they are in debt. And add all of these up.