Battery life seems to be almost entirely down to how much you're actually using it. My work Samsung Galaxy A5 (2017) lasts several days (really) because I only look do email and calendar stuff on it, a few times a day.

My iPhone 6s often lasts through the day and half way through the next, when I'm not doing much other than playing Spotify and using a bit of WhatsApp. If I'm actively using it, though, I have to plug it in towards the end of the day.