Play around with it, see how it works for you. Start your day with two 16 ounce glasses of water, before coffee or breakfast and drink plenty during the day. Drink a glass before lunch, and ditto before dinner. A gallon is certainly not too much, and again, if you live in a hot humid climate, it may not be enough. I have lived in both Texas - hot or hot and humid - and Minnesota - very cold but dry cold - and found that people did not drink enough water.
Players may also burn certain items in Bonfires to achieve effects. Bonfires serve as access points for Item Box drops. Due to the lack of a pause feature in Dark Souls 2, Bonfires are an integral point for players to take a break from play.
I think around 20 bosses in a Souls game is the sweet spot. It seems difficult to come up with fresh tactics to take on a new boss when you have too many. A lot of people have this problem with Dark Souls 2. As long as each boss encounter is new, mysterious, interesting, and scary then it has the right amount.