Three days ago I had to charge my Samsung Galaxy Note 3 at least twice a day.
Two days ago I replaced the battery in my 1.5 year old Samsung Galaxy Note 3 and charged it.
Two days later I have not recharged the battery, have hammered the phone usage and I still have 45% charge left!
I also have a 128Gb Sandisk card in place that contains a significant percentage of my music collection encoded as flac files. The 128Gb Samsung S6 is available in the UK for £699 whereas a Note 3 plus card cost me £680 so not much in it by price but I can't swap the card and my Note 3 has an additional 32Gb of internal storage.
Both of these factors mean that I won't be touching an S6, OR the Note 5 if it has the same limitations, with a bargepole.