It is rather a long time to go on wearing the same shirt. But the other characters have their own distinctive looks, including Violet, so it's really unfair to pick on the kid for this.
I wonder what it was that caused Schulz to decide on that distinctive zig-zag pattern, which is not a style of shirt that I am aware of as ever being popular, or at least not other than in the sense of referencing Peanuts.
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