I try to drink a liter before I leave the truck in the am...2 liters in the pack will get me by...then another liter on the drive home and or with dinner...sometimes more
4ish liters a day for me
that's very close to my experience as well (again cooler weather)- down water on the drive up (or at camp if backpacking), 2 liters (tw one liter bottles) in my pack and drink again when I get back to camp or vehicle
a few micropur/aqua tabs if I need more when hunting, only occasionally have I had to do this