I wrote one of the 24 words on the bottom of a piano key in 24 different pianos owned by 24 different clients. The first letter of the last names of those clients spell out my first car otherwise I wouldn’t remember them. I also kept no record of which key I wrote the word on, I will just have to look one by one until I find it in the piano. Assuming none of those people ever sell their pianos or move, I will always have access to my keys, but I will have to schedule 24 different piano tunings to find out what they are. Solid.