In the example I used, my peak load would be 4 liters, diminishing to 3 liters by the time I got to camp. I'd use 2 liters overnight (cooking supper and breakfast, and drinking), and leave with my "standard" 1 liter load, which would be enough to get me to water sometime late in the morning. (That's typical for the part of the country I hike in; other climates might require modification of my numbers to fit those conditions.) So, I'd be carrying 6 to 8 pounds of water most of an afternoon - not the end of the world, but definitely noticeable as I climbed the hill, and definitely more than enough to overwhelm a lightweight suspension like the one in my 32L pack.