Here are some tips to help you get the longest battery life and on screen time possible on your S5.
1. Root and debloat (Sprint and Samsung apps). More details here.
2a. Download Greenify from the Play Store and Greenify apps that you see waking your device (ie: Twitter, Facebook, Play Store, Google Search, etc.)
-----2b. Buy Greenify donate version and you can Greenify apps and still receive notifications from those apps!
3. When you go to sleep, turn on power saving mode and turn ON the following options within power saving mode: block background data, restrict performance (with everything checked).
4. At around 5-10% left, turn on ultra power saving mode to help get you through the rest of the day/night!
5. Don't have a million apps installed, a rogue app can deplete your battery (through wakelocks, background CPU usage, etc.) and it only takes one bad app to spoil your whole battery!
6. If you don't use GMail, or Facebook or Twitter, etc alot, then turn OFF auto sync for those apps.
7a. Go to Google Settings, then Location, then Google laction reporting and turn location reporting OFF.and Mode on Power Saving.
-----7b. Go to Android Device Manager in Google settings and turn off "remotely locate this device".
8a. Turn dark mode on for apps that have this option.
-----8b. Download and install "blacked out apps".
9. Turn off things such as smart stay, smart pause (rarely every works for me anyway) OFF.
10. Keep your brightness low if possible (cloudy day, night time, indoors, etc.).
Feel free to add any.
Screenies: Was literally using non stop, to compare my S4 would only go to 3hr 10min on screen time (highest I got out of the whole time I had it). Was in good signal area most of the time, but also sometimes I was in a not so great signal area. Anyways, I'm xtremely happy with 5hrs on screen time and almost a day total! Barely had my phone in my pocket the whole day/night!