I haven't really had a hobby until last summer, when I took up collecting banknotes. Growing up in the USSR, I had a few imperial notes as a kid and wanted to expand my "collection", but didn't actually start in earnest until decades later. Got a few late 19th / early 20th century pre-revolution notes, and then found myself in the abyss of Russian Civil War, where every city and local municipality were printing their own money. Anyways, it's a journey without an end, and I saw an interviewee describing this hobby as a "sickness, do not start", which sort of resonated.
As a history lover with appreciation for tactile aspects of history (love 100+ year old books), this scratches this itch better than anything else, while leaving me wanting more. I research and write up every banknote I acquire, and the sense of history I get from browsing my album is like nothing else.
For anyone interested, here are the photos of my collection circa end of last year: https://imgur.com/a/zmCXd8l