[zingmars]

It depends on how often he uses his phone and where he backpacks. Being in a low-signal environment will eat up a lot of battery even on a feature phone plus having screens 5x bigger than feature phones also lead to more battery usage when being used. My old OnePlus3 which at this point is only used for alarms and has apps set to auto update (doze is on, but battery saver is off) in the background lasts around a month before I have to charge it again.