I use my iPhone for most photos, texting, etc if in cell range ..which is often high up. I also use it for mapping via the Delorme inReach app which does not require cell reception to work. I then pair it with the inReach if I need to send messages and am not in coverage. I have also started using a headlamp that recharges via USB , and carrying an larger Anker Powercore battery.
I can get 2 -5 days off the iPhone depending on usage. Usually 5 days per inReach charge once again depending on usage. With the Anker I can get 4 phone recharges ... or probably 3 and an inReach recharge ... or probably 2 phone / 1 inReach / several headlamp charges. I sleep with the phone in my pocket or in my bag, the headlamp on my neck , and if I am using the inReach , then often the inReach in my bag. I sometimes even upload directly to Instagram or Facebook in the wilderness (I know sort of anti wilderness there ... but it's also sort of part of the gig ).