Jim wrote:

<<What do you call an aspect that conveys the notion of "henceforth" aka
now on" & "from then on"?>>

Inceptive plus habitual?

The action in question is going to happen continually or habitually, so that
characterizes it as habitual.   The
"from now on" or "from then on" part focuses on the start of the action.
So, for example, I wasn't born checking
my e-mail, but I now do it regularly.   Thus, there was a time when the
habitual action of me checking my e-mail
began (even though I didn't know it would then), and so the inceptive focuses
on that part of the habitual act.
The "from then on" vs. "from now on" part is just a difference in tense.

That's *one* way to conceptualize it, anyway.

"sunly eleSkarez ygralleryf ydZZixelje je ox2mejze."
"No eternal reward will forgive us now for wasting the dawn."

-Jim Morrison