Sure, they're not as essential as food and water, but trekking poles can be a great aid to long-distance hikers, especially in rocky or slippery areas where keeping your balance is both tricky and necessary. Steve Silberberg of Fitpacking says that a wooden staff can work just fine as can old ski poles, especially if you don't want to spend any money. But there are other options that are a little more versatile, such as those that collapse and are easily packed into luggage on a plane. Besides being an extra arm or leg when you need to keep your balance, trekking poles have other uses on a long expedition. "They can be used with a tarp as part of a shelter lowering the weight carried," says Silberberg.