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. To the optimist, the glass is half full. To the pessimist, the glass is half empty. To the engineer, the glass is twice as big as it needs to be.