Seriously, take care of your body. I was a strapping young guy who was never sick and who could shrug off anything. I spent 25 years riding some of the fastest motorcycles on the planet, shooting assault rifles for fun, blasting heavy metal as loud as it would go and working in the engine rooms of ships for 5 years as a merchant mariner. I had a great time.
The funny thing is I could have still done it all and not felt a single ill effect if I had just been smarter. I could have brushed after meals, I could have used my hearing protection every time, I cold have eaten better and taken a little better care of myself. But seriously, I was indestructible. The worst part is, people really did warn me, I was just too stupid to listen.