We got my son the SE2 for his bday when it came out--he was 13 at the time and we promised him he could get a phone when he was in 8th grade. SE2 was at a good price and feature set for a starter phone, so that's what we went with. What I guess I didn't realize until I lived with a teenager is that they hammer those phone batteries ALL. DAY. LONG. For everything. Constant barrage of FaceTime calls, texts, Snapchat, gaming, web surfing, homework, etc. He has a pretty powerful gaming PC in his room, his Chromebook from school, and an iPad and none of them have seen much usage since he got the iPhone.
Long story short--by this year the battery was at 79% health and he was carrying it around with an Anker battery pack attached just as a matter of course every day. For this year's birthday we upgraded him to an iPhone 13. He still can't believe it when he checks the percentage at the end of the day and it's only half dead.