What to look for when visiting an apartment in Germany?

It is better to come early, go around the building and the neighborhood and check for sources of noise or other irritants: cafes, businesses, night clubs (!).
Open the windows in the apartment and listen, perhaps from the street comes the noise from the main road, which overlooks the windows, or the noise of the subway. The same goes for smells.
How is the apartment heated? You need to be sure that all the rooms are warm enough.
Ask if the apartment has a storage room, closet or attic. Look at them.
Pay attention to whether the ceiling heights are enough for your cabinets or shelves.
Be sure to check if the landlord can pick up things you don’t need from the apartment (large and unnecessary furniture, old TV, etc.). This is even worth insisting in case of failure.
Is there an antenna for the TV? Is there a Wi-Fi router? You need to be sure that, after settling in, you can use the existing Internet or connect it.
It is necessary to clarify the performance of all available household appliances. If something is not there or something is not working, you should learn about the possibility of installation or repair.
Check to what extent you can make changes to the apartment. Drill holes in the walls or glue wallpaper.
If you have a car, you should know if there is a garage or parking space.
It would be useful to find out from the owner about the infrastructure in the area. How close is the nearest supermarket, public transport, whether there are kindergartens, schools, etc.