No KS at all with a 45-degree roof, because you lose about 1 meter of usable floor space on the roof sides, as you can hardly use this low area. You then knee-wall back to one meter. But that actually makes sense if you need less space in the attic than on the ground floor, e.g. parents’ area also on the ground floor and only 3 children's rooms plus a bathroom in the attic. Downstairs you have, say, 100 sqm, roughly 60 in the attic. If you distribute rooms conventionally, meaning you need as much space upstairs as on the ground floor, it makes sense to build with a KS right away. But I wouldn’t go below a 125 cm knee wall so you can place beds in the area underneath and still comfortably get in and sit there. Then personal tastes come into play: some don’t like slopes, others do. Plus, depending on that, storage space results. Ultimately, the KS arises from individual needs in combination with the requirements in the development plan, such as how high the house is allowed to be, which roof pitch, which eaves height, etc., and the floor plan. So I wouldn’t give a blanket recommendation for anything, because there is nothing that’s better, as it depends individually on the plot (large or small) and the residents. It’s all an interplay – one affects the other. Sorry..., it was about costs (I forgot). They naturally also depend on individuality. Because if you build without an attic (KS with 30-degree roof pitch), you may have to create storage space elsewhere, which causes additional costs.