I thought the phone automatically put the least-used Apps into suspended mode? Mine gives me daily updates on the least used Apps it has suspended.
But my early experience of just a few days use is that the battery life is not impressive. I have push email for work, as well as WhatsApp, WeChat and Line running all day - again for work. I'm a heavy user with regular email and call use throughout the day, but have WIFI for part of the day, brightness about mid way. For me, a normal working days is around 12 hours, but the battery seems to last about 9 hours, so I need to find a top-up charge. The charging is very fast, but would be better if I could get through a whole day and just charge at night.
I could probably disable some features, but that kind of defeats the purpose of having a (very) smart phone. My last phone (Sony Z5) was no better, but my smug Apple-wielding colleagues can manage a full day of similar use on a single charge. Also, a friend with a Samsung A7, who watches Facebook Live all day - can manage 2 days on one charge.