Surprised a search for caffeine doesn't find anything on the page.

Having given up soda around college (and never getting into coffee, and rarely drinking alcohol), almost 20 years later I'm glad I have the ability to drink just a little bit and get a good short burst of energy.

Treat caffeine as you'd treat aspirin, or bandages, especially when you're younger and you really do have an efficient power generator, and ability to do more with less. You'll have less of a tolerance you need to beat to get the same effect when you're older.