I try to get devices that use AA cells as much as possible. That lets me use rechargeable NiMH AA cells whenever I can recharge them but also allows for the option to buy regular cells if necessary. And I carry a 4-cell AA holder that recharges the cells from either a solar cell panel or from USB and can in turn recharge/power USB devices, incl. my phone. This gives the flexibility to move AA cells between devices as needed - i.e. if my phone battery dies just when I want to make a call to a motel I can take the cells out of my camera and put them into the AA holder with USB output to power the phone.

In developed areas it's usually pretty easy to find an outlet to recharge my AA cells. Many campgrounds have outlets available and otherwise I'll ask at a restaurant where I stop to eat if I can plug my charger in somewhere. The solar panel recharge option is more for backpacking trips.