LPT: Always carry a pen and small notebook with you for scribbling notes, numbers, shopping lists, or anything that will be forgotten. You will also have an in-case wallet if someone steals it.

I've been carrying a pen and notebook with me for 20 years since a high school teacher gave us a similar lesson. I don't remember losing my wallet, but I remember having it stolen when I had a black A5 notebook in my back pocket. <br><br>TLDR: Always carry a pen and small notebook.