We’re sure all Harry Potter die-hards think they’ve noticed just about every detail imaginable in both the book and movie series—or at least have tried to. As far as the films go, there are definitely new things to see with each fresh viewing, including seemingly minor details you might not have even thought were intentional. For example, did you ever notice that after Harry Potter and the Chamber of Secrets, the students at Hogwarts almost abandoned their robes entirely and began dressing like everyday Muggles? Well, that was on purpose.
In the first two films, wearing the Hogwarts uniform was considered very important and the kids were seen wearing their robes at nearly all times. But in 2004's Harry Potter and the Prisoner of Azkaban, the students hardly ever wear their robes outside of the classroom. That's because costume designer Jany Temime, who worked on the last six films, had a different vision for the kids when she was brought on to the project.
“I thought that they should look normal, that they should look like normal kids,” Temime told InStyle in 2017. “I wanted a real feel. I wanted to make Harry Potter not a little story that you read in bed but something real. Because at the end of the day, they are teenagers coming from dysfunctional families, all of them, and then living together in a boarding school and all those kids have special gifts."
The third film is also when the students began to mature a bit, so it would make sense that they'd grow tired of their childhood robes and want to dress for themselves. So yes, they did dress like Muggles. But they also dressed like the teenagers they were.