At the moment I think the most expensive hobby are my watches, even though I haven't bought anything nice in a decade... Just paid the equivalent of $450 for a service and repair of a semi-old Omega ... and just now got quoted more than the double for the corresponding full serivce a little older Rolex.
On the other hand, I'd rather pay to service older stuff that will continue to work for a few more decades than to buy an Apple Watch or something else that will be outdated and with a dead battery in just a couple of years.