When do realizations occur? Don't know. Realizations on the cushion and off the cushion. Moments where we say "Oh. i get it.That's what's happening when I get angry, lazy etc.." Moments where we say nothing at all (dropping, silent understanding). To sit Zazen, on and off the cushion is to study the self.
They come and they go (realizations). There is no need to keep track of them; however, our memory serves us well when we gain some clarity through mind and BODY. We continue to get on the cushion in the morning or evening, perhaps late at night. That's the point.
The harder you try to manufacturer something, the faster it will blow up in your face. Same with experiences "Got to let them go." and even letting go of the letting go. Basically being what you are. However, realization is a bit different and forgetting that is just ignorance. Attaching to it about the same as forgetting it. Yet we continue, not worrying about it, but just noticing, realizing, learning, and dropping.
Do you know? Are you certain? Trust the precepts when clarity and wisdom wains. If not, you'll probably learn eventually. That's when the invisible Zen teacher smacks you on the ass and says "I told you so."
To all those beginners. Stick with it. I believe there comes a point where you are aware of certain habits that you have, and how sitting Zazen is actually beneficial and "it Works" (for lack of a better word). What is this "working"? Well, it might be clarity, balance, peace, or wisdom.
I say believe because, well, I'm not sure. I need to sit more, understand more, see more, but I have a good guess. Let's not dwell in the realm of experts.
Sticking with it "is it" I think. What happens when we don't search or try to do anything in our practice, but just continue to sit and continue to notice and live our life. Realizations and life continues morning through night. We notice, don't notice. Realize, don't realize. Make supper with delusion. Make supper with clarity and on until infinity.