update: Despite careful calculation, we are overall about 13,000 euros over the planned budget and are glad to have included this amount for "surprises." We decided, in the course of the bathroom renovation, to have the old copper pipes from the 80s, i.e., the water supply, replaced. Additionally, we decided to completely renew the ground floor flooring (which consisted of Mediterranean-style tiles...), mainly also because my boyfriend discovered his love for working with the hammer drill/percussion drill and, inspired by removing tiles in the bathrooms, also freed the entire hallway, kitchen, living, and dining area from tiles. - In this respect, I can only advise budgeting a little extra. At first, I thought we would come exactly to the planned sum, but the above-mentioned work then suddenly fell into the category: Better do it now - once you live in it, no one wants to tear out the old water pipes anymore, etc. - certainly not voluntarily...