You’re familiar with the concept of setting an alarm to wake you up. You’ve come across this before. But I think this is new:

Set an alarm for when you have to go to bed

We all stay up later than we should given how early we have to rise tomorrow. And this tells you when to go to bed. It’s not ever going to be a shock to you since you choose the time but still, it works.

It’s like the alarm switches you into going-to-bed mode. Switches your head into it, switches your head away from whatever’s occupying you.