[marconey]

Switching to greyscale on iOS really helps reduce the attractiveness of wasting time

Settings->Accessibility->Display&Text->Color Filters

And you can activate with triple-click of side button also

Settings->Accessibility->Accessibility Shortcut->Color Filters

[jakub_g]

On Android this is called "Bedtime mode". You can also have a shortcut in the menu that slides from top.

[euroderf]

Yes, greyscale works. Eye candy is seductively seductive. Shiny! Shiny!