Regarding caffeine, I would drink a lot of soda each day, like 4+ Mexican cokes. The first month is terrible. You will have an initial withdrawal, then just be in a slump. I am the type of programmer to work on side projects after work and I couldn't. I decided to give it a month, but was legit considering starting again just because of that.
First month mega slump. Second month it's getting better. After that you're no longer dependent.
It's amazing how dependent everyone is on it. You hear, oh it doesn't really affect me, I just like the flavor of coffee, but I don't buy it. People are super addicted and coping. Caffeine doesn't give yourl energy, it just takes away the symptoms of your withdrawal.
Note, it did not fix my sleep schedule. Bright screens are kinda the last factor I can blame for that so I'm experimenting with eink and reflective lcd screens.
You don't need it. Water is the one true beverage. It's amazing how little water most people drink.