And I mean power. Battery power.
What happens if you are travelling to Africa and are not sure how much access you will have to reliable power? How will you charge your batteries?
My tip of the day: bring a small 12V DC to 115V AC power inverter. You can buy these at your local hardware store (Home depot, Canadian Tyre).
Because guess what. You will always have access to, or be driving around in, cars, and these cars have cigarette lighter outputs. You can bring a small inverter like this – small is key, and to charge camera batteries or a PC you need little power. So charge your spare battery while you are driving!