One of the things I love about hiking in the southwest is the use of cairns. Cairns are piles of rocks that help mark the trails, and in this rocky terrain they're often the only way to know you're on the right path. I can't count the number of times I've stood at a cairn, straining to see the next one, or taken tentative steps forward hoping to see a cairn up ahead.
For me, cairns make trail hiking in the southwest more like real life than following easy, well-worn trails in other parts of the country. Most of the time, my life is one of looking for the next marker that I'm on the right path, and trusting that future markers will be there.
Cairns are also a chance to add a rock (and a prayer if you wish) of your own. That way, you can signal the people behind you that they're on the right path too.