As a longtime user of f.lux I was ecstatic to see Apple address the issue of screen temperature. It's one of those things you don't realize how badly you need until you use it for awhile. To make a long story short, f.lux changes the color of your Mac's screen based on your location. Full brightness during daylight and gradually changing to a darker and orangish tint as the sun goes down. Use it for a week and then turn it off. It's like getting stabbed in the eye with a fork.

I downloaded the iOS 9.3 beta earlier this week and immediately turned on Night Shift, Apple's own version of f.lux for iOS. After a few days of testing it's exactly what I'd hoped it would be. The difference is amazing.

There's plenty of research on the effects of using screens before bed, and any little bit to help is worth it.