For the first few weeks of using my S7 I was averaging around 12 hours before my battery was completely dead, which meant it was pretty much out of juice by the time I finished work. Someone recommended I try a factory reset, which I reluctantly did and to be honest wasn’t expecting it to make a difference at all. The battery now lasts completely through the day and typically I put it on the charger at bedtime with around 20% left. Same usage as before, exactly the same App’s.
Not sure what difference the factory reset made, but it’s pretty much doubled my battery life. I perhaps wonder whether I’d copied something bad across from my S6 using the Smart Switch app, as typically I used to get pretty poor battery life on my S6 also, and maybe the complete wipe cleared that issue, but just guessing really.