I never rely on a phone whilst traveling (driving, cycling, hiking). When driving I mostly use built in car GPS or take a secondary dash mount GPS for longer journeys.

When on feet I use one primary eTrex with maps, and always have a cheap secondary hand held GPS without the maps. Plus a paper map. And a set of extra AA batteries.

Google search, maps and other good things you have on a smartphone are nice, but it's way too unreliable to my taste. Battery life is crap, and without a connection the phone is pretty useless, unless you use a mapping app that can download map data. In which case I'd rather use a dedicated mapping device.

EDIT: Obviously all the equipment can't replace common sense. If you see you can't go any further - don't. Even if all your electronic devices tell you otherwise.