There are two things I have to have within arm's reach at all times: lip balm and water. I usually drink two or three 20-ounce tumblers every night (sometimes just water, sometimes Italian sodas. I have a Soda Stream, so I always have fizzy water), and I don't have a clue how much I drink during the day. I have a 20-ounce tumbler at work that I just keep refilling all day. When I'm at work, after 9am, it's all water (before 9am is coffee time), and I tend to drink even more when I'm stressed. My best guess is five refills (plus my evening beverages) on a typical day, but I wouldn't be surprised to find out it's more than that. On the rare occasions I forget to drink enough water, I have some tattoos that get raised when I'm dehydrated, so if I can feel those, I drop everything and drink. I just like water. I have ever since I was very small. It's a family joke that you could tell where I had been by my trail of half-empty water glasses. On the down side, I frequently drink so much so quickly that my stomach hurts, but it's better than eating too much cheese, so I don't worry about it because I know it will go away in ten minutes or so.