Wild trails may be easy enough to follow for some time: one just continues in the direction that is passable without tromping through thickets, crushing delicate plantlife, scrambling over slopes, and submerging oneself in water or mud.
But you do have to pay attention. These trails are always changing, in accordance with the principle of least resistance. Stream courses are always changing. Rocks are rolling off of hills and resettling. Slopes are eroding. Trees are falling over. Rapid plant growth in the spring and summer, and die-off in the fall and winter may affect lines of travel.
The humans - and even the animals - that regularly use the trails, and maintain them by compacting them, may decide scrambling over a new set of fallen logs, erosions, or plant growth is just not worth the effort, and may redirect their path through a better course, subtly altering the trail in turn. And then the trail has changed.
