The importance of these free resources is best illustrated by those who have been pushed to the edge:
For long-distance hikers on the Pacific Crest Trail, purchasing individual USGS maps for the entire route can be prohibitively expensive. Many instead use free printable topo maps, mailing sections to post offices along their route to save weight and money. Topo Map Free
If you are planning your own excursion, these are some of the most trusted sources for free topographic data: Offline Use - CalTopo Training The importance of these free resources is best
Hadi Nazari survived nearly two weeks lost in Kosciuszko National Park, surviving on berries and sheer will. His story highlights how easily one can lose their way in the "unforgiving wilderness" without precise navigation tools. Topo Map Free