I drink a lot of coffee daily. I only make instant coffee. I love a nice filter coffee though.I mostly write commercially for a living these days.
I wouldn't be able to earn a crust without coffee. Lots of it.
I have a stove top pressure pot, a cafetiere, and a pour over thingy for a mug to take a paper filter. I also have these wee coffee bags you fill yourself.
I buy beans in large quantities and grind as I need them. Haven't yet roasted beans myself. (Fnar!)
I recently learned about the temperature control elements of the stove top pot that have made a huge difference to flavour.
I have three proper does per day.
A good bucket mug of cafetiere brew in the morning. A half mug of espresso about 11 and a cappuccino type thing before 3.
And I sleep like a labrador!
I get a headache on the extremely rare days I don't manage to drink any coffee.
When I was doing pro plus for my dissertations I think I had a bottle of them and was tipping them into my hand and just taking a few extra each time.....because I thought that would make me more alert and able to pull all nighters until the things were finished.
I don't think it improved my concentration on my work at all. I couldn't sleep but I think that was more to do with having not much content for my dissertation and having 1000s of words to write about things I had no interest in....We had to do a "dissertation" for core English Lit and Language options so too real choice in the courses/I had no interest in them at all. I delayed writing them, couldn't get hold of materials I needed in time, found some not very great books to quote from/use and ended up trying to make some waffle relevant somehow.....In reality the "dissertations" were not that long, but creating 1000s of words of content with nothing of interest/relevance to write about was very difficult. Progress was really slow (how surprising!).....
I look back on my undergraduate days and wonder how I managed to do a degree at all. The 3 years of a degree seemed never ending....
I will admit I try not to drink any caffeine in the late afternoon/evening. I don't sleep well but never did.