Special repayment, saving or consumption?

- The ETF return must be significantly higher than the interest portion to be paid, which is reduced by the special repayment

About 30% higher than the interest, assuming the transfer of the tax-free allowance. With the current interest rate of 0.x - 1.x % on average over 10 years, that should easily be achievable.
With interest rates of 3%, like I have (and maybe you too), the calculation looks a bit different.

- Shortening the loan term through special repayment and being able to say faster "it belongs to me and not the bank"

That is not necessarily correct.
If I saved maybe 5,000€ in interest with a 10,000€ special repayment over 15 years, but earned an additional 10,000€ with ETFs in the same period and then bring that in after 15 years, there will be 5,000€ less principal outstanding after 15 years.
Then the loan with special repayment might be paid off after 19 years, but the loan partly repaid with the ETF portfolio could be paid off already after 18 years.

Of course, if, like you, it was paid off in 10 years, then your statement is correct. But few people will probably be able to do that.

Consumption increased in many industries because suddenly people were just sitting at home and needed things they didn’t need (to that extent) before. Home office workstation (is not always provided by the employer, officially this is called mobile working), groceries, toilet paper (remember that? There was a whole thread about it), house & garden etc. pp

Phew folks, you’re posting texts here so fast that it’s hardly possible to respond anymore.

Which safe, risk-free investment yields more than a building loan costs?

As stated in the post you quoted, fixed-term deposit.
The calculation example can be found earlier in the thread, but since I’m also too lazy: 10-year fixed interest period, 60% loan-to-value, costs currently about 0.5%. Against that stands, for example, the 10-year fixed deposit of VW Bank with 1.6% interest. Deposit protection included. RK1.

Completely understandable, everything financially totally correct – see leverage effect.

Arbitrage

Any investment that yields more money than prepayment only pays off if I commit to it for more than 10-15 years, that’s just a fact...

Nope, see example above.
Otherwise, of course, you always have to consider equal investment periods. The prepayment on your loan, which ends in two years, has exactly the same reduced effect as a 2-year fixed deposit. In the case of a higher-risk investment, long-term commitment is of course highly recommended.

In a family of four with average earners and a single-family house, I internally have a completely different structure. I have entirely different needs and characteristics.

The asset structure is generally decisive. There is no black or white, as already said.
However, one can suggest to consider proportionality. A (owner-occupied) property is for almost everyone a gigantic chunk in their own asset structure. "Having no debt" is a feeling, not rational. You can try to ‘counteract’ that, because you miss out on a lot, namely the very good chance for a much faster debt repayment than would be possible with prepayment.

Therefore I don’t necessarily find this comparison accurate.

Then leave it, it is/was yours

If I can say after 15 years that my loan is paid off and I have €600 less to pay monthly, then that is not comparable with:

--> Meanwhile my money is working and in 10 years it is worth significantly more than if I hadn’t put the money into prepayment. Life circumstances can change here, crises can arise, etc... Also the emotional factor plays a huge role! What you label may not seem risky but it is! Not from an entrepreneurial view, but a private one!

I agree with the arguments, but pro "capital formation" and not pro prepayment.
The money in the portfolio is almost instantly liquid, instead of tied up "in a lump." If I have a crisis, I can access it much easier.
You also mix monthly liquidity with capital formation. Of course it can be pleasant to pay less monthly rate to be more flexible. My approach also allows that, and from the start, not only after 10 years ("liquidate KFW component").

Always remember: prepayment is only possible as a percentage share per year... I can’t just suddenly repay my credit in full overnight as soon as I am able to retrieve my long-term invested capital after 15 years.

Yes, you can. After 10 years you have a termination right at any time with 6 months’ notice, for any amount.
That must also be considered when you pay for prepayment rights with a higher interest rate – after 10 years they are unlimited and practically available at any time anyway.

And as you yourself mentioned: "Equity funds, with some risk." A prepayment has 0% risk. If I need the money after 10 years but find myself in a crisis then I have to be able to ride out that crisis. Money that I invest in equity funds must, in my opinion, be money that I don’t need and that is basically "irrelevant" to me at first. This may certainly be the case for some borrowers, but definitely not for all!

You are mixing the first sentence now. I presented a fixed-term deposit as the risk-free variant. That is equally risk-free as prepayment and more profitable after taxes.
Later in the text I of course suggest a share of assets in higher-risk investments. Everyone can choose the ratio as they like, but one misses a huge lever for wealth building if one only invests in the house.

There were some opinions here that one should live now.
I always find the middle ground sensible. Live now yes, but not excessively. Prepay yes, but not down to the last € on the account, but also keep reserves in account, instant access savings and ETFs.
That certainly doesn’t make you rich, but you are well prepared for crises.

As long as even in crisis times assets > loans, you might be in debt but not over-indebted.

I can only agree with that. A balance is required.
I neither live and work now to become as rich (or retire overly quickly) as possible, nor should the future be ignored (everything on credit, consumer debts, urge or even compulsion for expensive car/vacations/etc).

Especially for them, I couldn't understand how that could happen, since during Corona you were more or less forced to stay almost only at home. You couldn't do anything or barely anything -> consumption automatically went down -> more money to save or for special repayments via

Consumption did not necessarily go down. Online shopping. New TV, garden furniture, 3D printer, etc. Many here are used to ordering everything. But yes, actually there must be more money available. It was the same for us. 800 km commuting per week gone, canteen gone, shopping only in the village. Unfortunately, the library was also closed. Our supplier of books, audiobooks, DVDs, and games. 10 cents per medium for children. We then really had to increase funding massively.

Exactly. In consumer electronics, things were especially intense (of course, mostly online). The entrepreneur with a poor view of people then sees themselves confirmed in the belief that people only really work under supervision... In reality, working hours only shift and overlap more with private time when you are only at home. For example, I work even more often before 8 and after 7 p.m. than before. But in between, I sometimes take one to three hours off. Errands in between happen more often when you don't have a commute in between.

I actually only know people with a 10-year fixed interest period, who will likely still need to refinance at least 300 to 400k after the 10 years. Most likely, this will not be a problem, as the low interest rate policy will continue for at least another 20 years. But it could also turn out differently, and then it will get uncomfortable. We wanted security and chose 20 years, generously assuming that this security costs us about 20,000 euros.

But I only did it because of my wife; I would actually have taken a risk here as well. However, I still always have at least 100k buffer in the account to remain able to act if something goes wrong.