“Always carry a headlamp.” This was my motto for years. It is less useful now than it once was, as I generally seperate out my hiking gear from my travel gear better, and as my iPhone tends to have a light on it when I need one. However, after too many times trying to maneuver through catacombs in Malta, sewers in Paris, or caves in the Adirondacks, I tend to think that carrying an extra few ounces isn’t the worst thing to do in the world. A headlamp is also incredibly helpful for late night or early morning runs; sometimes, those are the only times you can run, especially in places like Indonesia, when there are motorists everywhere during the day and it is too warm for long distances.
Black Diamond generally makes incredible headlamps, and you can pick them up in most places. I gave this one away to a friend by accident in Tokyo, who needed it for a late night run. I picked up another one the next week.