Calling him "Lord" Sasuke is exactly why people have trouble taking Sasuke fans seriously when they want to debate seriously -_-
Regarding the change in clothes - since they are now in a war, I don't think Naruto will have the time to go home and quickly change into something else.
I think Naruto doesn't have as much change in his clothing as Sasuke, because Naruto is drawn the most. It's easier to draw just a jacket and pants, then something with a lot of details. Not saying this is true, but I think it's a plausible reason for why Naruto changes his clothes the least.