Everyone knows multitasking is bad. Usually because of performance on the tasks and context switching.
There is another reason, maybe even more important, why it is bad. It is about stuff like checking your phone while watching the TV. Doing multiple stuff while you are “resting”, especially in the evening.
Doing this keeps you engaged much more, than simply just watching TV or just going through social media. And it is so much harder to feel tired in this way.
I have noticed this on myself quite often. Watching a football match when I am tired leads to me knocking off pretty quickly, prompting me to go to bed. But, if I scroll through my RSS feeds while the ball is being put down on the line of scrimmage, or during time out, I can keep watching without noticing that I am tired.
And the next morning the difference in being rested is quite noticeable.
Pick one “resting” activity and focus on that.