We are having our apartment handover next week. Theoretical question: in case they want to "blame" us and consequently charging us for e.g. repainting the walls and I disagree with their view, can I refuse signing the protocol and have it later checked with a lawyer as an example or challenge it further in any way?

Why I am asking this. The paint on the walls has a life span of 8 years and we live in the apartment for 7 years. Technically, if they need repainting, we should pay 7 / 8ths of the total cost. BUT: The walls were not freshly painted from the agency when we moved it. They were in decent condition but the previous tenants had painted themselves certain walls, and the difference in color was slightly visible in certain areas (pictures taken in the original handover and are part of our protocol). So the agency has not painted the apartment for more than 8 years (I'd say since 2006 that the apartment was built). I can explain all of this to them during the handover, but if we have a disagreement, how this normally ends up? One more piece of info, the walls will be thoroughly cleaned and any visible marks removed, but the "magic sponge" I use changes the texture (flattens it), so if the light hits it in certain angles can be visible...

Don't sign the protocol at handover if you don't agree with what's written there! You won't have your deposit returned until you and the landlord agree, but you'll gain time to decide what to do next.

I think you've got the aged paint issue the wrong way around. If paint has a life of 8 years and you've rented there for 7, you could theoretically be liable for 1/8 of the cost of repainting.

I doubt you'll have any problems, though, as most likely the landlord will want to renovate the apartment and won't seek anything from you -- assuming you've been cooperative tenants...?

Thanks for the input, and thanks for the math correction, I've written it the other way around

Pay and join the mietverband in your area. They'll help you by explaining your rights and telling you how to proceed with the landlord.

Correct but it's not 8 years from when you rented but from when it was last done.

Isn't there some bit of info where they have to show proof of the last time it was painted in order to charge you for it? As in they can't just turn around and say it was painted before you moved in, but they need to show the receipts from when it was last done?

Indeed.