Hello
I guess the answer is likely to be that you should use whatever you want and there are many ways to skin a cat but I’m after general wise advice from those with more experience.
I usually turn off a power socket and lights in a room before I go to bed. Should I use an automation to do this or create a scene and simply trigger the scene?
Do you have a way to trigger that automation?
I’ve recently set up Matterbridge to be able to control entities via Alexa locally. I would be using that mainly. I can also add a button to trigger a helper on/off and use that to trigger the automation. This is what made me consider using a scene instead but wanted to see what people are doing in case there is better logic and smarter ways to do this.
I believe what to is asking is, do you have anything that happens always at the same time that you can relate to this action?
Could it be, that you set your phone on charge and the time is always after 21:00?
Do you use your smart toothbrush right after switching this lights off?
Do you have a sensor in the bed to know that you are in bed?
Do you have motorised blinds that you close that you could trigger on?
Is there any other action that happens between you deciding to go to bed and actually falling asleep that you can define that is visible in Home Assistant?
Thank you very much to both of you for replying.
The answer is no to the above. The only thing I do is turn off wifi on the tablet by my bed
Ok… Does the tablet have the Home Assistant app installed?
Yes. It does.
In that case you could use this as your trigger in the automation.
But that requires the tablet to have a 3/4/5G connection to report that you disabled the wifi.
That’s the thing. I considered doing that but I turn off the wifi so that the tablet goes completely offline 
I love the idea of a bed sensor. I hadn’t even considered the possibility. I’ve got manual folding shutters for the windows so it’s not possible to automate these. They would be closed anyway by my other half.
As it seems now, a scene or even a group that switches them both of at the same time seems enough.
But when you get more sensors or figure out a way to detect something then it’s easy to change.
There is also the sleep confidence sensor on the app.
It’s currently 40% sure my spouse is sleeping at work
Oh wow. I didn’t even know it’s got that sensor. I need to play more with teh app. I was put off when I enabled location tracking and it drained my battery massively. This was a long time ago so maybe I should play more with the app.
LOL regarding your other half. That made my day. Thank you Sir