I use my device mostly as a camera and a flashlight when I work night shift. I only need the device 4 times during those 8 hours, 2 minutes each time the most (8 minutes total)
Would it make sense to turn the device off after using it or is the amount of battery I’m gonna save negligible?
Another question would be: Would it make sense to turn the device off when I leave the workplace? 16 hours of savings, or would this also be negligible?
I think it depends on the device and how far you’ve gone to prevent energy use on it while it’s idle. It sounds like you probably don’t have any third-party apps installed, so that’s a good start, but removing anything else you don’t use would be good, too. Or at least disabling them as much as possible.
Depending on the actual usage, which will vary from device to device and especially OS to OS, I’d either choose to turn it off after work, or off after each time I’m done using it for an hour or more.
The other factors are how hard it is to charge, and how long it takes to boot when you need to use it. If it’s easy to charge, I’d probably not worry about it much. If it’s slow to boot, I’d lean towards not shutting it off during work.