I sometimes tend to be slightly disorganized. And frankly, my short term memory is nothing to boast about, so I tend to misplace things...and people. Occasionally I come across an individual in church records or a census and think, this person could very well be a sister or brother, parent, cousin--somehow related to an ancestor I'm researching. So what do I do? I begin researching this new person to see if I can find a connection of course, all the while scribbling notes hopefully in a notebook, but often as not it's on a piece of scrap paper because I'm not sure this person is even a family member and then I promptly loose said piece of paper or forget which notebook my notes are in. Even if I place my notes in a word document I am perfectly capable of misplacing the file, though I'm getting much better at using consistent labeling.
Having tired of this, I now enter the person of interest where I think they may fit in my family tree using my genealogy software. I make a note that this is an unproven relationship, and insert my notes. Sometimes I even make the person's middle name "Maybe" just to amuse myself. This accomplishes two things, when I want to resume my research on this person the notes are at my fingertips, and it also serves to remind me, (because of that short term memory thing),