My father is like that. He drinks a lot of coffee, and even at night. Drinking coffee a few hours before bed doesn't mess with his sleeping though, and I'm thinking he already has a high tolerance to caffeine. He buys different kinds of beans, mixes them, and blends them himself. He even has different ways of making them, like pour overs, drip, and a boiling one where the coffee rises from the bottom. I'm the opposite, and I'm just a social drinker.