I stopped trusting GPS after they failed to work on 2 outdoor adventures. 2 Trips, 2 Different GPS units and 2 different types of failures.

1 could not get any signal through the trees, and then said we were off the screen yet we were on a very very very old and popular hwy.

1 could not get any signal through the clouds and snow. We were technically lost on our quads in a snow storm... just when we needed the GPS most it failed. We made our way back, stumbled upon a sheriff learned the trails looped and crossed over, etc. Either way we found our way back by using our brains and thinking.

So, I don't use a GPS anymore. I use trail maps, and google earth shots that I print off and use my BRAIN.

This reminds me I need to sell my other GPS UNIT.

FWIW Both were different model garmins, not $100 cheap either.