I have noticed that in Captain America: Civil War, Peter Parker's room is smaller, has a grey wallpaper, and twin beds, then in Spider-Man: Homecoming, he has a larger room, brighter lighting, still grey wallpaper, and a bunk bed, but in Spider-Man: Far from Home, his room is the same one that was in Captain America: Civil War. Why is this?
The apartment in Spider-Man: Far From Home is not the same as the one from Captain America: Civil War I believe. However, it is a different one and they do explain this in the film. May and Peter were both Snapped and so when they Blipped back they lost their home and had to move. This is part of the reason May starts the charity she does.
May: When I Blipped back to my apartment, the family that was living there was very confused. The wife thought that I was a mistress. The grandma thought that I was a ghost. It was really a mess. Thank you for coming out to support those who have been displaced by the Blip.
Spider-Man: Far From Home
I’m not sure there’s an official reason for the change from Civil War to Homecoming. It’s probably something we’re supposed to just have suspension of disbelief over and assume it’s the same apartment. Either that or they move and just didn’t think it was worthwhile talking about in the film. There is speculation, and it isn’t half bad, that Peter spent some of the “Stark Internship” money on getting a better apartment and so that’s why they moved.
Note though that the two films were made closely together and the appearance in Civil War is very brief. There’s potential that out of universe they just didn’t want the hassle of getting them the same for a short scene.