If you're comfortable sharing what amount "retire forever money" is for you, I'd be interested in what that number is. See profile for DM options if you don't want to post it publicly!
It wobbles around depending on my mood. At the most basic level, though, enough to pay off the mortgage, do a few fun things, and create a fund to draw down at 3.5% per year covering two good incomes – so somewhere in the $6-8m zone. If I were sick or had to stop working for some critical reason though, obviously that would drop pretty quick given lack of options.