My T used to only wear blue. Blue pants, blue shirt, and always the same two or three shirts as well.
He's also had the same blue shoes for the last three years.
About two years ago I saw him wear a red shirt once. Then it stopped again for almost a year, and now he wears that one red shirt more often. Maybe once a month.

I was definitely surprised and a bit irritated the first time he wore red. I don't necessarily think I'd have been bothered if he'd have changed his appearance in any way like that before, but after him looking essentially the same for over a year, it was a bit weird at first.
I've gotten used to it now, but I still observe what he's wearing every time.