I would contest the idea that the brain operates on cycles. It is much less organized than that.

I would agree, but it's a workable short-hand / analogy for most of my use-cases.

I (feel like I) know and remember more today than I ever have, but starting around age 50 I must admit, I am also forgetting things and have quite possibly already forgotten more than I currently know. One hopes one is hanging on to "the important stuff..."