We are 44 and 37 years old. Yes, the current house has about 80 m², but it is spread over 2 levels. About 50 on the ground floor (eat-in kitchen, small bathroom, small living room) and upstairs there is a bedroom with closets, storage space, etc. However, the stairs to the upper floor are quite steep, which unfortunately cannot be changed without major effort. And you definitely can’t go up and down so easily when you’re older. Hence the consideration to build an extension and use the upstairs only as an "attic" (storage room). We don’t have a basement. The property is relatively large, so space-wise the extension would not be a problem. Of course, you can probably do many other great things with the money, but for us it is important that we don’t have to move out later because we are not as mobile. At the moment we are still quite young, but we are already thinking about what will come later.