I denied their usefulness for many years but for hauling heavy loads they should be considered mandatory even on a good trail. When the legs get tired the poles can save a nasty stumble/fall.
For backpacking in general above treeline in Coloradfo I'd also highly recommend the collapsible styled poles. The alpine zone can be filled with thick shrubs and bushes over wet rivulets and uneven terrain and these will help prevent twisted ankles and the like. I did have to try out severl versions before finding a good collapsible pole though. Typical problems include: inadvertently collapsing on you, lower sections falling off, small screws and parts that are just not back-country friendly. Years ago I finally settled on Black Diamond's Approach poles due to their very compact size when collapsed, reliability, and length when extended (I'm 6'5"). They have performed brilliantly for many years in everything from backcountry snowboarding to hunting and hiking.
I still keep mine mostly on the pack but they (at least 1) are always there on anything but a day pack.
