Battery Saver modes are essential when you need your phone to last as long as possible at a moment's notice. Standard Battery Saver limits background activity and switches on Dark theme, reducing visual effects that can tax a battery.
Battery anxiety is the worst, and Battery Saver is a no-brainer feature that helps at just the right time. Standard Battery Saver steps in at the 20% mark, dims the interface, drops the screen refresh rate, and pauses some non-essential background data.