I just go by feel, and by observation and experience. Which it seems you are as well, and it apparently is working for you.
But, if you want to, there's the option of counting calories (approximately). Many websites will do this for you, along with various apps, etc.
Even if you do that just once, or every now and then, you might get a better idea of where you're at, and so on.
I'm exactly the same height as you, weigh a tiny bit less, but have a lower body fat %. All in all, quite similar. Anyway, I'd say you're doing okay. And yes, you can see the progress there, with the two images posted.
41yo, 6', ~200lbs