My current net income is about 3.1k at the moment and we have taken out a loan of 275k (construction is currently ongoing).
Since I have 2 children (8 and 1) and my girlfriend only receives 150€ parental allowance, I chose the loan so that the monthly installment is only 1000€.
That, of course, is not enough to repay the loan within a reasonable period! However, I have 10% special repayment and fixed interest rates for up to 30 years.
In other words, I only "have to" pay 1000€ monthly, but can pay significantly more if there is enough money left over.
With child benefit and parental allowance, we then have about 3600€ net income available in total, and it shouldn’t be much less than that... if I had a significantly higher installment than 1000€, we would have to restrict ourselves here and there... and we do not live luxuriously.
We could get married, of course, then there would be a few hundred € additional per month...
In September my girlfriend will start working part-time again and then about ~1050€ will be added (1200 - 150 parental allowance).
About 400€ more will be saved for special repayments, so the installment will initially be at 1400€/month...
This is just an example of what financing can look like with children, etc... flexibility was important to me so that in an emergency it can be managed with only one income... therefore low initial repayments and high special repayment options...