Halfway up a ridge last summer I ran out of water, got dizzy, and had to sit on a rock for forty minutes while my buddy finished the summit without me. Never again. If you're someone who does 8+ mile hikes and keeps underestimating how much water you need β or you're tired of juggling loose bottles that leak all over your granola bars β I tested a ridiculous number of hydration packs so you can skip the trial and error.