alt Hacker NewsI have my phone in monochrome (i.e. greyscale) mode and just subjectively it's much easier to look at especially at night. I have it at the lowest brightness and it's still very readable. Human eyesight is basically monochrome in low light settings anyway.
I have an accessibility shortcut to turn my screen greyscale with triple taps but I kept turning it off so I could see the clues on sudoku and now I've forgotten I even had this for almost a year
Low brightness is great though. I didn't realize most of the battery drain on a phone is often just the screen. Lowering the brightness to as little as I need has been great for battery life