The other day I saw a guy in town wearing a t-shirt with the word "c--t" written across it, jeans sagged to show the bottom hem of his boxer shorts and a baseball cap. Do I judge someone who dresses like that? Of course I do. (Admittedly, his girlfriend walking next to him had a t-shirt with the "parental advisory" sign on it, which amused me)
If, on the other hand, you're talking about basic t-shirts and jeans, and basic hygiene, after that, I don't care much at all. My boyfriend has an interesting fashion sense (we're both into vintage fashion) and his style is a little "all over the place", but it suits him. I work in a clothes shop that sells more upper-end men's clothes, so I sometimes have to help them out with that, which can be interesting!