Model Railroading.

It’s not the worst, but it requires all the key ingredients - you need to own a home large enough to have a ‘spare’ room, which means you’ve got disposable income. And displaying the trains is almost as much fun as running them, so you end building shelves and shelves, which then sprawl out to the rest of the house. Only to realize you’re missing the ‘key’ one from that set, got to go find that, obviously.

And then of course you can’t throw away the boxes, because that would lower the resale value, so you need to rent a second storage unit. Not that you would ever sell them of course. But your kids will be sitting on a goldmine!

And that’s just the collection portion. It’s a crafty hobby, from making scenery & waterfalls & little trees all the way to the special paints to make the engines look aged. That will need a room as well.

And now that we’ve got the train shelves in the kitchen, you know, I could put a food themed railroad on the table there. Yes I already have the desert themed one in the train room and the prairie themed one in the living room and the snow theme layout in the hallway, but I don’t have a silly one. No of course the Halloween theme one doesn’t count.

Crafters are definitely up there, overall - but I think wargamers might beat them. Hundreds to thousands of models, paints, brushes, terrain, carrying cases, books - it adds up to a hoard of epic proportions. That’s just personal experience though. Lego fans can also get to be out there, and TCG players.

The reptile-keeping hobby. ):

Cycling can get bad. Some dudes have a garage full of $20k of bikes.

I am on the low end of the bike hoarding spectrum. I have two very modestly priced bikes (one road, one fat) and a 20” box of parts and accessories. You could count the 4 water bottles in the cupboard, 4 bike shorts in the drawer, and 6 bike jerseys in the closet as well. 2 pairs of bike shoes, a hook of tires and tubes in the garage, oh god never mind I have it bad.

My first answer would have been retro game collecting, but that’s already been discussed, so I’ll posit custom PC building. That’s a hobby rife with keeping spare parts “just in case”.

Source: Self

Any “retro” collection. Old video games, for instance. In many cases, the barrier to entry is sky high, because there are very few old consoles or games on the market; The collectors have bought all of them, and are never planning on selling.

Is this a place to cast shade or self reflect? In the former experimental scientist. They have closets of oscilliscopes, vacuum pumps, cryostats. Enough to furnish 3 or more labs. They always say they’ll use it, but the pile only gets bigger.

For me, I have the opposite problen in general. I throw everything away and end up buying or making new shit. Worst is probably code. Fuck making a repo. This is a one off. I can write the same code 3 times before I keep it, but I like to say that is what makes me a decent programmer. And I’ll keep telling myself that until I die.

Automotive, back yards becoming junkyards of old cars that “will be fixed one day”. Piles of used oil, broken parts, tools that are for only one purpose. Extra car parts, that may or may not work.

The “hobby carpenter” and handymen sort. Guys who like building stuff and own land to do it on. So much crap and sub par materials. Hundreds of salvaged half rotten 2x4s that might be enough to hold a person with a couple dozen of them. Shit tons of insulation just getting soaked outside, tons of random cinder blocks and bricks, etc. Add in a side of drywall, random carpet scraps, tons of various wiring, and a massive assortment of tools that have probably seen more house dust than wood dust.

Not taking a dig at these guys, but you have to be realistic with what you can accomplish. Unless its a crazy good deal/find that you know you will use or be able to give away, don’t touch it.

For the sake of space and organization, just buy materials for the project RIGHT before you build it, and AFTER you plan EVERYTHING about it. Account for EVERY piece you need so you never need to buy a bunch extra “just in case”.

I know people are giving some very good examples, but a pet that can easily turn into a hoarding hobby is hamsters. You get one, get super attached, and then three years later whoopsie doodle, the living room is filled floor to ceiling with cages for all twelve of your little dudes.

This is just due to how much space the little guys need. In the wild hamsters will viciously defend miles of land, so bigger cages are always better. As a general rule, an ideal cage should have 900 sq inches of space and be at least 2 feet deep to allow several inches of bedding. So, one little dude will take up at least 12.5 cubic feet of your living room, or .07 cubic smoots for our friends across the pond. This adds up fast, and it can be easy to get in over your head because each individual little dude requires so little cage cleaning per month.

You must have met my wife. My oath, the amount of fucking yarn and fabric in her stacked to the ceiling sewing room is horrendous. She couldn’t knit enough blankets in her lifetime to use up half of it.

Hobby electronics?

Need a small part? Better buy 10 in case you break one and because it’s only marginally more expensive than getting one. Now repeat for every project you do

I’ve read some really good answers, but imo there isn’t a worst type. This will vary from person to person, some people don’t get buried under the whatever they buy and others do, regardless of what their interests are.

Every collecting hobby is definitionally a hoarding hobby.

Backpacking. I have a big plastic bin filled with equipment that I decided to go another direction with.

But makers are the kings of hobby hoarding, just look at Adam Savage. He has parts for things he hasn’t even thought of building. He has a plethora of tools that overlap entirely just because the set of tools is closer to a given work aspect. Walls of bins with various degrees of filled because he bought 100 of something a decade ago that may have a future use.