I wear a watch on all my hikes, the LaCrosse Technologies XG-55 got it for 60 bucks on e-bay new. This has an altimeter alarm compass, and all the jazz you'd expect in a digital watch, like a thermometer. I use it as my prime navigation tool. Knowing my pace averages 2 miles an hour throughout the day, I can tell how many miles I went, plus the altimeter combined with the approximate mileage from my hiking time, will show what trail junctions im nearing and how much more climbing i need to do. Indespensible I think on trail.