I make a mark on the back of my hand in ball-point and ONLY rub it off when the job is done. Eq (using your example) if I knew I had to lock a door on the way out I would write either an 'L'(ocked) or a D(oor) on the back of my hand.
Because I stick to the 'mental rules' of only rubbing it off once the task is completed, if I'm uncertain if I've done the thing / task I can look down to my hand to see if that mark is still there or not. If it is - U-Turn time!
It Works pretty well (as always, mileage may vary) even for multiple things if needed although the random letters/marks on the back of your hand can make people curious but if it does I simply say - It's a list of stuff I need to do.
Field Notes 3.5" x 5.5" notebooks are the size of a folded index card with only a few pages in them. So they comfortably fit in my pocket. Staple bound is relatively weak, but their relatively cheap price means that you can just keep buying them as they wear out (moving your legs / walking / etc. etc. slowly weakens the paper and tears it apart).
Realistically speaking, a Field Notes 3.5 x 5.5 is well balanced: I seem to run out of space roughly as the staple binding wears out. (I know people don't want to "waste paper" but.... I haven't found a good strategy for that. The small size and "disposable" nature of these Field Note books are superior in my experience)
Pentel Kerry is a "shrinking" pencil. It has a small size when its stored, but when you pull the cap off and put it on the back, it "grows" slightly and has a better balance for writing. Its a very slight effect, but the "smaller stored size" makes for a nifty pocket-pencil.
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> I make a mark on the back of my hand in ball-point and ONLY rub it off when the job is done. Eq (using your example) if I knew I had to lock a door on the way out I would write either an 'L'(ocked) or a D(oor) on the back of my hand.
Never erase in your pocket notebook (despite using a pencil). Just add more information later: cross out old information with new dates, if you're out of space write down a page-number where you can see more information on a particular subject.
Because I stick to the 'mental rules' of only rubbing it off once the task is completed, if I'm uncertain if I've done the thing / task I can look down to my hand to see if that mark is still there or not. If it is - U-Turn time!
It Works pretty well (as always, mileage may vary) even for multiple things if needed although the random letters/marks on the back of your hand can make people curious but if it does I simply say - It's a list of stuff I need to do.