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I agree generally with avoiding redundancy. If you ar me backpacking with others, perhaps you could also divvy up the weight. But when it comes to safety, there are some things where redundancy makes sense. I carry stormproof matches and a lighter, for example. I also carry a water filter and Micropur tablets. If one doesn't work, you have the other just in case. And I've had more than one "just in case" situation occur.