In general, for larger residential construction projects (usually from 4 residential units), for commercial facilities and, if required by the development plan, open space design plans are necessary.
Does a single-family house fall under this?!
In general, it refers to the multi-family house. However, the sentence itself does not exclude a single-family house. It only says that generally it applies from 4 residential units. So it could also apply from the first residential unit if it is regulated that way.
No one wants to leave their house – their life – in old age. Only if it really, really no longer works. And then they usually don’t live much longer.
Well, whoever thinks from the age of 70 that life or better said the approaching death depends on the familiar living space should stay. But there are many whose brain cells still function so well that they find it revitalizing and life-sustaining to look for something more practical in a self-determined way. Ultimately, only paternalism is the generational problem of seniors or also the lack of willingness to make decisions. But that is an attitude towards life that does not necessarily belong here, unless one gets the addressed target group (future builders) to think about it.
It is not wrong to already think about the care of the garden now, but I think the conclusion is the wrong one.