Something I just learned, and I thought maybe other people wouldn't know it either.
I was adding some Font Awesome icons to my menus to make them pop a little more.
But I noticed that the login icon was closer to the text than the menu icon was. Normally I'd just toss in a to space it out a bit, but when i tried that it felt like it was too far away.
That's when I learned that there are HTML entities for other spacing options:   for a thin space, and   for an even smaller space. So I tried the thin space and voila.
Just right.
I've known about for 25-ish years now, but where have the other two been all my life? 🤣