If I'm really needing to cover some country I use two poles. I find them more helpful on steep downhills than the up hills. At least that's where it sms to help my knees the most. I have a pair of Leki's which have been through the ringer a few times, but they do work. However, I will be going with the external flip lock style next time.
PS- Don't let a horse step in one, it makes a bit harder to adjust...
