Houses without basements: Storage space, hobby basement?

Oh-oh. Our neighbor also built without a basement, without an attic, without a garage. HE'S CURSING! Do you already have children? I would think it over. Anyone without a basement needs compensation space even if they belong to the throwaway type. Certain things are simply not thrown away: tools, seasonal clothes, keepsakes, certain children's toys and so on and so forth. A house without enough storage space quickly becomes too small. Think carefully. I would reconsider the shed roof and instead build a gable roof.

We don't have a basement and I would only put things in the attic that our martens and mice can really use right now. So nothing.
However, we have two garages (currently filled with building materials and wood briquettes, the junk level there is zero). Furthermore, we have a small annex that is not heated. Bikes are stored there and unfortunately still some junk, but that comes from the previous owner and is being thrown away little by little. That means we are throwing away, actually more me. My husband would keep everything but I have moved so many times in my life that I appreciate the value of junk-free possessions more. After converting two winter gardens into living space, we still have a third one with 20 m2. There I keep my rabbits and my baby squirrel aviary as well as hay and currently still building materials.

The heating is located under the stairs in the living room, due to lack of alternatives... There would have been space elsewhere, but the way to the fireplace would then have been too far. In the house, in the basement floor (basement = living space) at the back, there is a kind of utility room area, but it is quite full with the inverter and electric boxes (two huge ones with one and a half to two square meters of surface area in total) as well as a 500 L buffer tank. There are still 2 sqm of a niche left for shelves where some boxes with junk are stored.

The hobby room is spread out over the entire house, before the renovation we had 10 rooms and 200 sqm of living space. Now only 5 more or less connected rooms throughout the house (most walls and doors were removed). There is plenty of space for all sorts of things, even enough for the ballet-gymnastics-yoga room (upstairs) as well as the PC-game-VoD room (downstairs).

Despite all the space, I still wouldn't start accumulating junk now. My in-laws have filled an entire room up to the ceiling with bulky waste, that would be too sad for me. Most of that junk is never needed again anyway and for everything else there is already a place in the living area.

5-year rule: if you haven’t used or touched something in the last 5 years, you won’t touch it in the next 50 years either. So get rid of it!

Of course, you can also make it a 2-year rule

I know it as the 1-year rule

We also have a desk, but two offset ones, so that the lower one on one side can serve as an attic (under 2 meters head height), which is accessible from the upper floor through a normal door.
In the higher desk, we have the two outer gable rooms with normal ceilings, so that from the gallery we have a door in the upper walls to store sports equipment (seasonal items), garden cushions, and change covers.
Additionally, in this area, that is on the upper floor gable side, there is a utility room only for washing. We also first considered leaving everything open on top (like you are considering now) but decided against it.
Unused seasonal clothing and shoes are hung in a built-in closet in the office. By the way, in the other half of the sliding door closet, the PC will find space on a built-in sliding work surface; if needed, the door can simply be slid open and the PC niche is ready to work.
In the utility room, we have paid attention to having a tech-free wall so that an Ikea kitchen unit without appliances can hold all tools, glasses, kitchen supplies, knickknacks, and more.
On the upper floor, we also have a dressing room that can still accommodate boxes in the upper area.
Memories are stored in boxes in the office; what you should absolutely forget is parking a leftover piece of furniture somewhere between. That is now posted on Ebay classifieds or Facebook and gone.
Just like with furniture problems, it might be similar with children’s gear/strollers, etc.
Outside behind the garage is a storage room (a garden shed is not allowed) for mowers, tools, and bicycles.

So if you have the option, it’s best to plan a universal room (guest/office/hobby) on the ground floor with one wall consisting only of cabinets.

You can also store boxes and cartons well on bedroom cabinets; in the hallway above the doors you can install shelves or wall cabinets for the same purpose.

Books can be nicely stored behind a podium staircase or at height (pitched roof) reachable with a ladder.

A stroller can also be parked in a box outside in the summer.

The space under the stairs should not be underestimated either: as a wardrobe or broom closet.

P.S. Internalize a few Feng-Shui rules, then you won’t have any fuss worries anymore

5-year rule: if you haven't needed or touched something in the last 5 years, you won't touch it in the next 50 years either. So get rid of it!

Of course, you can also make it a 2-year rule

Hey, my old Fleischmann setup with dozens of locomotives, cars, houses, Wiking/Herpa models, etc. is still waiting in the basement to be rebuilt – it won't go away even after the 5-year rule

And: with children, it's really not possible without an attic and/or basement – unless you have >200sqm of living/usable space... – or enormously large garage extensions.

So 180sqm of living/usable space with one child without a basement and 10sqm of attic is enough for us. But my wife is also very careful not to accumulate anything unnecessary.

We only have 135 sqm of living space. But children,... Without a basement, we would have a huge problem. Old children's clothes that the second child wears later, tents, sleeping bags, tools, sleds, decoration stuff, etc. That takes up 1.5 rooms in our basement. The car and bikes are in the garage, there is no room for anything else. In the garden shed are the lawn mower and the children's fleet of vehicles – here everything is full as well. I'm curious how you will solve this.