Mental mechanisms to use when paper or HandHeld are scarce. For instance if you lived 200 years ago and feather pens, even paper was probably a luxury how would you have kept contact lists, to-dos, appointments etc organized? For instance one way to remember a task without writing it down is to put an object in an unusual place i.e. put watch on right hand instead of left (if that  is the usual spot). I.e. if driving and an urgent task comes to mind. Or need to buy contact lens solution - put the empty bottle on your dresser the night before. Or techniques like envisioning winning before a tennis match then enacting it without thinking (of course subject to fitness, training etc) you enter a zone where your mind becomes like a computer with powers you can draw on without trying to control or keep track of every thought. Paper is messy and bothersome, HandHeld''''''s run out of batteries at the least convenient time; or worse - drop and break then it's heck to get the data into a new one. Yes there was a sync to your desktop but guess what that new virus going around just crashed that too. Meditation, mental arithmetic, even daydreaming makes more use of the power of the mind.