Good point.
I think we forget sometimes how hard it used to be, so what we may think is painstakingly slow to us, might still be too hard for some people.

I'll usually try to guage my lessons on the level of expertise it's under.
For extreme beginners, I'll go into over-explaning something.
But for intermediate to advanced lessons, there's an assumption that you're already at a level where you can understand what's happening.