I would consider myself as an medium-heavy user, meaning: ~3 hours of screen time a day, lots of browsing and texting, 5-8 min of calls, a little 2d gaming and listening to music.
I take it of the charger at 8AM and i normally go to bed at 12PM ...
Here you can dowload the flashable zip with the nexus camera and gallery app.
Just flash it with any recovery and it will ad the two apps. It wont change anything else.