Well, it depends. A few days before that I went 43 miles and only used two of those bottles. I never touched the third. It was 72 degrees and low humidity. It is more water than I usually need for 30+ miles, but it was around 88 degrees and above 90% humidity. That changes things. Also, maybe I do need more electrolytes. BUT - I still want to go at least 80 miles without support of any kind. I want to be able to carry plenty of water and food. I can't do that now.