I've been making a lot of my idea lists private just because they are crazy ideas or things I'm learning that have no interest to anyone else.
But, as I am on this "journey" of achieving a higher rank in chess than I had 25 years ago when I last played in tournaments, I am on a constant question to learn more.
The theory is this: as the brain ages, somethings slow down and some things get better.
What slows down: memory and calculation.
What gets better: pattern recognition and "wisdom".
Wisdom could be defined as being able to make better decisions based on the patterns you now recognize. Not everyone grows wisdom, and this is the hard part of getting older.
Because I have been playing in more tournaments I can directly see and even measure how my brain has changed.
Memory: much worse. Probably 50% worse or more.
Calculation ability: not as bad but not as good as it was when i was younger. Maybe best to say it this way: the volatility of this ability is high for me. Sometimes I am very good. but sometimes I am worse than I have ever been. Like equivalent to the first month I ever played back when I was 17 years old.
Here's my big problem: because the above two things for me were so good when I was younger I never really had to rely on wisdom.
I knew nothing about chess. I knew how to calculate and I was great at memorizing openings and crushing people right away.
Now I have to learn about chess. Concepts that I never cared about before like: space advantage, weak squares, open files, bishop pair, endgames, different pawn structures, etc.
Plus I have to learn more about stamina, mindset, etc. I never had to care about this before. It's really hard for me.
So I keep track now of what I learn. Here's an example of something I knew before but now have to learn in a deeper way. What to do with an Isolated Queen's Pawn.
I roughly knew before (don't let the pawn advance and exchange the bishop that controls the square in front of the IQP is the main things I knew). Now I have to learn deeper.
So I am studying the game Karpov-Uhlmann to get a better understanding. Again, some things are obvious to me but somethings are a bit deeper.
1. Karpov-Uhlman

This is the game. Notice that Black has an isolated queen's pawn. Which means no pawn can protect it and in an endgame (when fewer pieces are on board) it is almost enough to be winning for the other side.
This snapshot is from a video at ChessMood.com. Worth noting that Karpov was about to become the World Champion when Bobby Fischer refused to play and gave up the title.