Purchase opportunity for an old building from 1953, assistance with evaluation

If you have the time and the desire, then realize yourselves in the house! It’s definitely exciting to see it change over several years. Friends, who bought a 40-year-old house, also replaced all the windows within the last 5 years, installed completely new floors, and broke through walls (for an open-plan kitchen). They also completely renovated the bathroom with a walk-in shower and new tiles. A lot was done by themselves. And some things were tricked a bit. For example, the wooden wall paneling was simply painted white, so it no longer looks quite so outdated. From the inside, the house also looks very modern (plastered white/grey walls). Only the outside hasn’t been done, and you can tell. That’s why I would recommend that you also renovate the facade (not just for looks but also to keep energy costs low and to install an air-water heat pump + underfloor heating). Good luck with your project!

I'll write it all together because I find that more elegant than fragmented single-line quotes:

Get the building file, the sections are at least as informative as the floor plans (which will also be complete in it). The ground floor plan shown here was apparently created for the extension application regarding the conservatory along with the outdoor stairs. The windows of the conservatory are clearly visible in the plan; I suspect the outdoor stairs were only planned and never executed. The room unit "practice"/"vestibule" (and probably also the upper garage) are likely extensions as well, younger than the Kern-Haus, but older than the conservatory. The conservatory really seems to be slated; however, the grimy gray weather-side cladding is likely actually Eternit.

The seller's price expectations seem to already include too much future appreciation.

Topic of personal contribution... with "him" I don't necessarily assume a manual activity at 3,800 net. In any case, none that is still practiced daily. Also, in such salary ranges, often more than a 35-hour week is required or even shift work is done. Then 2 children on top...

Long story short: Are you sure you are not overestimating yourselves there?

Unfortunately, the time required, even as a hobby craftsman, for small things, is often massively underestimated. For every screw, clamp, etc. that the craftsman has somewhere in a box in the car, you drive to the hardware store, which costs an immense amount of time.

In addition, there are tons of tools that you can't do without, but which cost you a fortune both to buy and rent.

And then you also have to be able to do what you are doing. Otherwise, it doesn't look nice, is bad for the building in the long term, or even life-threatening, especially regarding the electrical work...

You really have a comfortable starting position for this house, but I would definitely have a large part done with the financial cushion. You also find craftsmen you can trust and learn a lot in the process to do a lot on your own later. Otherwise, the rest of your life completely falls by the wayside if it doesn’t end and you have to do it after work. And we are not talking about one year here...

And it’s just as was written above...the craftsman has everything there. Especially the small stuff is really annoying. Just to hang the upper cabinets in the kitchen, we drove three times only to find out that we have to improvise. Our friend had the different lengths right in the car. (And we even have two hardware stores within 1km... still every time half an hour gone)

That's how it is, yes. I only drove around the Kreis again on Monday because I wanted to replace the hoses on the downpipe with a rainwater pipe, now that winter is coming, the hose can't handle larger amounts of rain. Off to the hardware store, wanted to get 87° bends and pipe made of titanium zinc, DN100... but they don't have such bends there. So back again, measure, think... then back to the hardware store and instead bought KG DN110 and somehow fiddled it on. Almost 2 hours for a task that looks totally simple at first glance...

For the roof box I had planned 2 days for 3 coats of paint, it ended up being 4... etc.

With such

That's right, yes. I only drove around the district again on Monday because I wanted to replace the hoses on the downpipe with rainwater pipes, now that winter is coming, the hose can't handle larger amounts of rain.
Off to the hardware store, wanted to get 87° elbows and pipe made of titanium zinc, DN100... but they don't have such elbows there.
So back again, measure, think... then back to the hardware store and instead bought KG DN110 and somehow fiddled it on.
Almost 2 hours for a task that seems totally simple at first glance...

For the roof box I had planned 2 days for 3 coats of paint, ended up being 4... etc.

*laugh* We can contribute plenty of such examples too. If you're not an expert, everything just takes three times as long (at least).