Hobby? This is not a hobby for me, flashlights are tools, and I like to talk about good tools, especially during the times when I'm in the market for new ones, and just after. I'm here because this year, I bought three new flashlights to completely replace the ones I was previously using, and might purchase one or two more.
At this very moment, I am awaiting my postal carrier and a new CatEye LED taillamp for my bicycle.
Everyone should own at least one really high quality flashlight. Actually, everyone should own at least a few really high quality flashlights. One EDC, one tactical, and probably one for the house toolkit. I like to go backpacking/camping, so I also have a headlamp. My tactical light does double duty as my bicycle headlamp, and because it has a huge 21700 battery, is great for power outages. The last power outage here was more than a day. I had to toss most of the contents of my refrigerator and freezer, because I can't run a generator in an apartment.
I'm old enough that I'm of a generation that regards having a good pocket knife and a good pen, among other personal carry items, as essentials of daily living. A good flashlight is something that I would have loved to have when I was younger, but it wasn't until about 20 years ago that high quality LED flashlights really made the idea of an EDC flashlight viable.
Of course, prior to that, I was in IT consulting, and that means carrying a big briefcase filled with whatever I might need on the road, and with over 30 years of stage tech and pro audio engineering experience, I had been carrying a Mini Mag-Lite since the mid 1980s.
That's not a hobby, that's just daily life.