There's a lot to be said about noticing your confusion. If you want to have a better understanding of things, that's the first step – finding the gaps in your understanding that still need to be filled in (don't worry, there are plenty).
But I don't hear people talking about noticing other elements of your internal state. Can you tell when you're tired? I know many people that seem to not be able to notice unless they're exhausted. You aren't born knowing how, and the light and stimulation from screens (as well as other people) masks it pretty well. But needing to be alone, in a dark room, with nothing to occupy you, just to figure out if you're tired? You need a more sensitive detector than that if you want to be well rested.
Similarly, when was the last time you noticed you were frustrated or distraught? Sometimes someone can make you feel weird without doing anything obviously objectionable – I actually suspect some people do this on purpose.
I've had a couple moments, where I realize, oh hey, even if I don't know why, my mind is running too fast, I can't go anywhere. I've noticed if I can't focus or can only focus on stupid things.
And then I meditate. Or just sit silently. Or try to sleep. Or try to figure out what bothered me. Or just try to rest.
This is not always an instant process.
But it's got such great returns on investment that I'm skeptical of people who have meditation as (solely) an element of their routine. Wouldn't they get much better results when using it tactically to respond to situations they notice?
But again, noticing isn't an easy thing. We don't have very many tools to help us, but let me propose this: task-switching is a good indicator for my internal mental state. When I'm healthy, I can task-switch pretty rarely. When I'm not doing as well, I find I'm opening apps on my phone a lot, diverging my activities more and more. It's possible that phone addition or distraction isn't a cause, but an effect, of something being amiss.
Of course, things can be both. The reason I take a second to pause when I notice things going poorly is precisely because the rapid task switching doesn't get me out of a funk. I might even finish everything I need to get done, but I'll still be en-funk-ified.
I'm curious if there are more thing we can notice, clues to make us look actively at potentially important things, like our mental health. What are the signs that could help us be better stewards of ourselves?