I was and still am a life-long model railroader (avatar, heh). Which sometimes feels hard to distinguish from "hoarding" some days, but I do have and impose limits (roadnames / eras / prototypes)... still, it's hard to stop. I have too many locos and freight cars to count. But one "exception" from the modeling aspect, is collecting certain trains for the sake of it. I've developed a fondness for older metal and wood kits, as well as early (50's and older) plastic. There was an entirely different philosophical approach to modeling within the limits of materials back then, and yet some of the craftsmanship was astounding and holds up reasonably well today.
I also collect trains from Tyco. Which were mostly garbage from the 70's till they quit in 1993... but there is a real jeckyl-hyde aspect to them: for all the garbage they made, some stuff was actually quite nice to almost awesome. And while they made enough Burlington Northern boxcars to stretch to the moon and back, I have found others that are incredibly rare - like 1 of as few as 100, 50, or even 10...? I've also acquired R&D items from the factory, hand-painted test samples, catalog photo one-offs, and the like. The whole company was America, Inc. for good and bad, before that became a cliche' of modern SOP.
Model Railroading was an uncanny springboard into restoring pinball machines: electronics, mechanisms, woodwork (bench / cabinet), painting... the particular OCD aspects... the 1 translations of skills, approaches, and tools are amazing. But as an end product, pins are far more interactive for kids and guests