@himbovoorhees there's a kinda rule of thirds.
by the one third point, you should have a clear idea of the problem, the problems from that problem, and the general way to go.
by the 2/3 mark, you should be setting up for the climax. most of the pieces should be on the page and you're about to have them all combine and kick shit off
and the 3/3 mark... well that's the end