Might be different but repainting your apartment is expected from renters here to the point that contracts often state you need to do it every X years and before moving out.
i've always assumed that the letting's agency will _definitely_ take my deposit if i fsck with the walls
Definitely not normal here although in my current house I did repaint with good paint, but I had to ask the owner permission first.
I think that the owner needing to repaint between tenants is considered normal wear and tear here.
I agree that a dehumidifier helps but you basically need one in every room. Where I live you can easily take out 10 liters a day from every room during the humid season (which is the maximum capacity of the machine I rented).