As a recommended rule of thumb for the amount of maintenance costs to be expected in housing ownership, one can say:
"From the purchase price 0.8% to 1.0% annually from the completion of the construction."
Purchase price of the apartment (90 m²): EUR 145.000, -
of which annual reserve 0.8% to 1.0%: EUR 1.160 to EUR 1.450
per m² living space: EUR 1.07 to EUR 1.34 / month.
Of course, construction quality and building equipment also have an influence on the height.