Condominium purchase - feasibility study

The mistake is that you somehow assume that you get an apartment of this caliber for free. Anyone who still hasn't realized that homeownership is increasingly becoming a luxury good is unfortunately beyond help.

Look at the apartment, location, contracts, and decide whether you can and want to afford it. No one here can decide for you whether this is "your" apartment.

The total amount including interest is 670,000 euros

Better stop calculating the total sum including all interest. It simply doesn’t help. It only has negative psychological effects.
You have it in your own hands: repay faster and the interest costs decrease.

Just look at the monthly installment and the remaining debt after the fixed interest period, that’s enough.

I know that I won't get such an apartment for free and that no one can decide that for me. Just see this as a diary. An apartment is a luxury, the question is whether I want to afford it - that's true. I have worked my way up from a socially disadvantaged family and therefore do not handle such sums lightly, as I am absolutely not used to it. And I do not want to end up there again with my family, where I came from. Just for understanding my thought processes.

I'll try.

I simply assume that almost everyone who is active here is moving the largest sum of their life with an investment in the mid six-figure range, so for me that has nothing to do with background. I also do not come from wealthy circumstances, but if you do not sign contracts carelessly and think through possible scenarios in advance, then it should work out. Deciding on an apartment and then hesitating before the investment is not sensible in any case. Apart from that: if the apartment project fails, then with proper planning it probably will not be because you overextended yourself from the start. Something like that can also just happen, with or without real estate.

A tip: If you want to know how not to do it, then watch "Zuhause im Glück". Even though the events are always portrayed dramatically, I almost always see that the families have taken on way too much from the beginning. If something then happens, collapse is programmed, but I don’t see that with your planning.

For a property built in 2015, be sure to request the minutes of the WEG meetings for review beforehand and search them for indications of quarrelsome co-owners. Also check the amount of the maintenance reserve. There are now different rules of thumb for calculating this. But if it is below €2.50/m²/year, I would start to be concerned even with the relatively young building. At least inquire whether an increase in the maintenance reserve has already been planned or decided upon, since after 5 years the developer's warranty expires. So, exactly this year.

Yep, I'm taking it all apart. Good point regarding IHR - and warranty - the latter I didn't have in mind off the top of my head. I'll get back to you with an update.