New construction or buy house, built in '91

The house price is definitely negotiable (-10% would be the minimum for me).

There are "other interested parties" and it is "the most beautiful plot" in the area -- why would the seller want to concede?

It depends on the situation whether the price is negotiable. In Hannover, the prices are also a basis for negotiation, but upwards, meaning whoever adds the most on top gets the contract. Unfortunately, we've already missed out on a few houses because of this.

Ok, then the standard land value will also settle at around €110 and will have little to do with the "old" development area next door. Then your land price also fits. But you can see from this that there is obviously a difference between the area of the existing property with €80 standard land value and the new development area with ~€110 standard land value, i.e., the location is rated better in the new development area. If both locations work equally well for you, I would tend to go for the existing property, because less capital is tied up in the land there and with the same purchase price more capital is in the house.

In addition, a finished garden, possibly with shade-giving trees, is also worth its weight in gold.

You have to look at the backlog of repairs, but bathrooms from the 90s are just from the 90s. You can only replace it partially with difficulty, i.e., if you consider renovating the bathroom, it will quickly become a complete renovation. Then everything old comes out completely.

It is also important that carpets may still look good during the viewing and will be good for the trash after the owners move out. On the one hand, because furniture has stood on them for 25 years, on the other hand, because a lot of dirt is spread when moving out. For example, the carpets in our existing property still looked quite acceptable - after moving out they were worn out. Fortunately, we had already planned for that.

Best regards
Dirk Grafe

If you finance, please also consider that for existing properties the loan-to-value ratio is usually significantly higher, as the bank bases it on the market value (not necessarily the same as the sale price) minus a safety discount for the loan-to-value ratio. It can therefore happen that you have to provide significantly more equity for an existing property in order to obtain acceptable interest conditions.

We also bought a 1992 existing house a few weeks ago - but we won't move in until the end of May... meaning we still have many weeks of anticipation & impatience ahead of us. Except for all the invoices regarding additional costs (notary, land registry office, real estate agent, tax office), we are also enjoying it because, for stress reasons, we did not choose a new build. Of course, there will be this or that surprise (e.g. carpet as mentioned, or maybe the heating will fail in two years as in your case due to the year of construction, or whatever else) but I think you sometimes have those with new builds too - although you can more easily fall back on the 5-year warranty there, which is not possible here.
Tip regarding the heating: At least have the latest chimney sweep reports shown to you; they should be quite informative. And definitely take the expert advice!

Does it really have to "tingle"? On the one hand, it is indeed a great feeling when you think about the house. Imaginings like the wonderful garden, the large south-facing terrace with a distant view, etc. make you dream We also see the advantage of being able to move in without much renovation work and construction stress

No, it doesn't tingle for everyone. There are also those who just have a great feeling when they think about the house – when you already see your sofa standing in the living room in your mind, your gut has already spoken

However, there are always moments when you ask yourself whether this is a good idea, etc., and then you think, the bathroom is not so nice, actually I would prefer dark tiles to light ones, etc.... everything has its pros and cons.

These moments exist one way or another. Big steps always bring uncertainty about doing the right thing.
You can always renovate the bathroom later, and light tiles will also come back around sometime...
With an existing property, you usually get more than you can afford in a new build. Usually, the garden and the carport have to wait several years because money is missing. And also, not everything you actually want in the new build will be realized because of the cost.

At the moment we live in a quite modern, super-equipped apartment, so we are a bit spoilt. Some others would probably find the bathroom great.

I understand that: I also had a super chic apartment and bought a house from 1978. The bathroom was in Bahama beige, second-choice tiles (with gray dots in the glaze at intervals :mad , I barely fit in the bathtub, two huge sinks and a white irregular tile floor with these small onion-shaped tiles, so many grout lines – I didn’t want to step on those tiles barefoot until we fully renovated the bathroom after 2 years.
The kitchen was also horrible new, but all gray, even the walls glued with this plastic stuff. -> knocked it out and made a cozy kitchen corner from sterile new.

Maintenance backlog: old kitchen appliances, rubber seals in windows and doors, silicone joints, mold in the grout of the shower, ...
But in my opinion, these are not reasons to lower the price, but things you should/might have to renew.

Have fun in your finished garden wishes Yvonne