Another format for my daily map depends on a train ticket, either one that I bought and used at some point in the past, or one that I found on the street, or one that a friend brought home for me. And I must give a shout-out to those wonderful friends who are supplying me with tickets, museum brochures, flyers and just plain maps from their travels. I really appreciate what you have brought me!!!
My rule for this format: paste the ticket onto an index card, add a map. Thank the friend who brought it to me.
When I got home I inspected them closely and realized that this ticket wasn't from Hamburg at all but Graz -- almost 700 miles away in Austria. (I wonder how it got to the floor of the Hamburg station.) And noted that in my newly acquired collection of brochures was an ad for Graz tourism, complete with map! So it was easy to match the ticket with its map. I don't suppose I'll find that kind of coincidence again.