I don't go anywhere in the backcountry without my Garmin inReach. After years of exploration and near death, it's the one piece of gear that is always with me, no matter what. In fact, while I was just in Iceland for Ducati's Expedition Masters program, it was attached to my hip, too. I had cell reception, sure, but there was no chance I was going to head off into the unknown glacial wilds that are Iceland's public off-road trails without it.
However, in recent years, everyone's smartphones have become more and more reliant on satellite signals, with Apple and other manufacturers now incorporating satellite communication functionality with many of their devices. While not as foolproof as a bespoke satellite communicator, they're getting better and better. Still, I break phones, and wouldn't ever entrust my safety to them fully.
