Something I had noticed in the last year or so was a decrease in my memory's functioning, something that scared the bejesus out of me. The kinds of issues I noticed were smaller things like trouble remembering a name, recalling when I did an activity, etc. Apparently this is typical (in Silver Threads: Aging, Memory it's called "tip-of-the-tongue" memory loss), and it bothered the hell out of me. Both that article and Memory in the aging brain point out that there are significant reversible environmental and psychological factors that can impact memory, and that's where David Allen's Getting Things Done comes into play.
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