Of course the alternative, for this luddite, is to minimize the number of electronic gadgets! I take only my camera and my headlamp, neither of which uses rechargeable batteries. I take an extra set for my camera, but since I can turn off the LCD screen and use just the viewfinder (I deliberately bought one of the rare cameras that has this feature) I rarely use up the fresh batteries in the camera even if out for 10 days. By putting a fresh set of lithium batteries in the headlamp before the trip, I don't need to take extras for that. I also take a Personal Locator Beacon, but that battery can be changed only at the factory, and of course it's for use only in dire emergencies.

Since where I backpack there is no cell phone reception, I usually hide the turned-off phone in the depths of my car. I won't need it until returning from the trip--once I've driven into cell phone range (which may be up to an hour after leaving the trailhead), I use it to call the person to whom I've given my itinerary.