It’s like a lousy filing system. What made sense to you when an event happened may not be obvious to you when you need to recall the event.
As my own awareness of some “senior moments” has increased with age, I have looked for and found a method to improving my “filing system”, as you call it.
When younger, we were often able to do any number of very small tasks all day and almost automatically and did not frequently lose things - the “filing system” worked without 100% active conscious effort.
But, not so easily with age.
BUT, I have found that if, in my daily activities, I make an active and deliberate conscious statement to myself (only needs to be in my head, I don’t have to speak it out loud) of what I am doing when I do it (as in: “I’m setting the keys here”), and do so most importantly with the smaller tasks (most inclined to be done automatically too), then I pretty much forget nothing.
My “filing system” works better, when I very actively participate in it. I think this was less essential at a younger age.