I use a set of A-Z dividers in the back of my planner to keep up with projects and frequently used pages (other/older/less used pages are filed in a separate binder using the same A-Z dividers). The last time I took my boys to get their hair cut, the stylist asked me did I remember what size guards we used last time. I did not but when she figured out it was a size 4 I wrote it down on the back of the "H" divider page.
Today my hubby told me he didn't remember what size air filter to get and would have to take it down to get the right size. I asked him to tell me the size and wrote it down behind the "A" divider (and I told him to ask me next time)
Sometimes you need an extra level of protection where it wouldn't be prudent to write "safe combination" under S and you'll have to find a method for that. Giftie suggests taking the number and adding "1" to each. For example: 5472 becomes 6583. Sometimes I just write a number behind a certain divider and trust I know what it's about!
Do you do anything like this?