Maybe you have a trust fund. Maybe you'll have a wealthy spouse. But you never know when either one might run out. Don't mess too much with your hair or by the time you're 40 it will look 85. Be careful whose advice you buy, but be patient with those who supply it.
Advice is a form of nostalgia.
Dispensing it is a way of fishing the past from the disposal, wiping it off, painting over the ugly parts and recycling it for more than it's worth. But trust me on the sunscreen. I truly believe in the thread that connects this planet and this galaxy and so, it stands to reason the universe. I guess it starts with gravity and the moon. If the physical relationship between the Earth and moon can move mountains of water up and down every day, then it only stands to reason that the water in our bodies has to be affected as well.