I always hike with two poles. For all of my lifetime I have never had good balance and using two poles helps keep me on my feet especially with the pack on my back. A slick rock or tree root, start to go for a tumble, many times the poles have helped me get a footing. I also think that in my case the steep downhill runs with two poles are a little easier on the knees. The new lightweight telescoping poles do not seem to wear out my arms and just make hiking more enjoyable and in my case safer.