Change repayment rate - bank now requires new documents

If you really want to do it with 1% repayment (I would be uneasy about that), hopefully not too high anymore? Otherwise, you need an investment form where you can absolutely access the money when your interest rate period ends, because at the current roughly 4%, otherwise it will break your neck if there is still a lot left on the clock.

624 € is the current rate. Of that, 117 € currently goes to interest.

You have to explain that. I calculate exclusively with current fixed deposit interest rates. I would never go into ETFs with 13 years – that’s pure gambling. ETFs are for my retirement provision.

In what way is that risky? The only thing: you have to invest the money at a fixed interest rate. Whoever spends it, of course, has lost. With a good fixed interest rate, the debt is almost 10,000 € lower in the end than if you keep the rate high or make special repayments. The plan would be the complete repayment of the loan after 13 years.

But assuming something happens by then and it doesn’t work out: in what way are you worse off? Provided that the money is also saved at fixed interest?

So, I always take a little daily allowance interest with me and have a good feeling because my loan is getting smaller and smaller alongside the monthly 6.4% repayment.

Do the calculation on that. I don’t know your loan details, but depending on the situation, this (purely mental) security costs five-figure sums.

You have to explain that. I calculate exclusively with current fixed-term deposit interest rates. I would never invest in ETFs with a 13-year horizon – that is pure gambling. ETFs are part of my retirement provision.

I don’t know what your exact figures are, and your income, etc. There is always the risk that with the discrepancy in interest rates, the household service later might no longer fit the higher interest rate. But if there’s only so little remaining debt left that you can fully repay it in 13 years, then of course that’s irrelevant. Purely economically speaking, it would be "irrelevant" whether you repay the loan or invest the money elsewhere and possibly make a profit through the investment. I am just risk-averse here, because if the loan still has a large amount outstanding at the end of the fixed interest period, you are dependent again on how a bank assesses your financial situation. You are basically dependent on that. If you increase the repayment instead of reducing it, and have the loan paid off after 13 years, then you are on the safe side. Economically, however, as you rightly say, that may be disadvantageous.

As long as the money is invested in fixed-term deposits and the savings are used to partially repay the loan in the follow-up financing, there is no higher risk. Since you have more money, the remaining debt is even lower. The only real danger is that the money is misused. But you are responsible for that yourself.

I already mentioned the currency reform a few days ago.
Many laughed it off, but in my eyes, a currency reform is the only risk, aside from personal mistakes.

I’m really not a scaredy-cat, but after a pandemic and a war in Europe that is rather getting bigger instead of smaller, and China circling around Taiwan, it’s at least something worth discussing.
In the 1948 currency reform, debts were converted at 10:1, but assets at 100:6.5.
That means if instead of paying off your 100,000 credit, you had saved 100,000 in your savings account hoping to make a lump-sum repayment, you would still have 10,000 credit, but only 6,500 assets.
Therefore, you would be missing 50% of the assets for the lump-sum repayment.

The actual problem at this point does not lie in the conversion itself, but in what comes before. Whether it is war, hyperinflation, something else, or all of it together... nothing remains as it was. Starting from the question of the job to the question of where to get food or whether bullets are flying around your ears. Whereas the typical homeowner has reached an age where he is only called up for the Volkssturm ;)

I'm just risk-averse because if you still have a large amount left on the loan at the end of the fixed interest period,

I still don't understand. At the end of the fixed interest period (or anytime after 10 years) you should have all your ducks in a row and can then make a lump sum prepayment or legally "partially repay" – § 489 Building Code.

And that even with the extra interest you have saved.

Currency reform 1948

That can't be a serious consideration. There were other tricks for property owners then too: the Equalization of Burdens Act. I mean, you can mention it, of course. But the incredible destruction of World War II caused completely different problems than what could be used as a realistic comparison. In other words: if it happened again, considerations about fixed deposits or repayment would be completely irrelevant. You can't draw conclusions from the past to the future here either.