Old people have many bad habits and are not good at taking care of themselves. For example, leftovers can be eaten for several days at a time. Either you have no money or you are frugal.
China people still believe that they should lose all their teeth when they get old.
If you don't wash your teeth in time, maybe your grandfather will never know what tooth washing is, what dental floss is and what an electric toothbrush is.
It has nothing to do with feng shui. What age is it now? Believe in the party.