do you think hook should change clothes?

Well there is also his sexy red vest outfit but I agree he needs some modern clothes for hanging out in New York.

Many fairytale-characters wore only one outfit, that belongs to their personality. Also the most of Disney-heroes for example. Hook's clothing fits to him so much that I can't imagine anything else on him. I'm sure Hook took a bath in the Neverland rivers usually fully dressed, so he could washing out his clothes. :)
In fact: in former times pirates (and ordinary sailors too) always wore the the same clothes because that was the one. On the longway ships wasn't enough place for various clothes.

I agree, also he needs some modern clothes to wear so he doesn't stick out so much in New York.

*This is his "default outfit." ;P

YES GODDAMMIT!
I mean, it's a crazy awesome outfit, but seriously, how long has he been wearing that thing?! How often does he bathe and wash it? Change that shit, man!

Oi, he bathes quite frequently thank you. He says so himself when he was trying to get Henry for Rumple.
As for never changing his costume, he can sleep in that for all I care! Have any of you guys ever seen Doctor Who? People don't ask The Doctor why he doesn't change his clothes within regenerations. Granted The Doctor travels to mais places than Hook, but cheese.
Now hold on to your negative comments for a second. I do think he could change his vest once in awhile, thanks to black leather going with anything, but the main costume in general? No way! And why should he be the only one that has to change his outfit? Their costumes are a part of their characters. Change the costume, change the character! Honestly people, you don't ask any superheroes to change their outfits. Hook in leather is the best thing I've ever seen! Don't you change Hook!!!!