I too try to use minimal batteries. I don't take my cell phone because, at least out here in the west, most places I hike are out of cell phone range. In fact, I usually get out of cell phone range while driving my car to the trailhead. The only items with batteries that I take are my camera and my headlamp. I take one extra set (2 A cells) for the camera. For the headlamp, I start with fresh lithium batteries which will last several weeks.
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May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey