Im sure many people may have noticed this but among the straw hats, luffy, zoro ussop and chopper rarely have a change in outfits.
Nami's clothes often changes to a new one in almost every arc.
Robin also has some change of clothing
Sanji, well at least he changes his polo once in a while…
luffy wears the same red top and blue pants or shorts whatever you call it
zoro still wears the same white shirt and that green obi thing and black pants and boots
ussop has that jumper with no shirt under....except during the skypiea arc, he had that brown t-shirt on
chopper...er i wont mind him hes a reindeer,but at least he wears pants.
The only time zoro had a change of clothes was probably during drum island (since it was cold) and alabasta (since it was hot and its a desert).
I think zoro had different attires in arlong park, coz he stole that blue polo somewhere in arlongs lair. And during skypiea he had that blue sleeveless top on with the goggles!
As for luffy, well same in alabasta and drum...after that I only remember him wearing the same attire. Oh he did have a different outfit during davy back fight, that afro look!
I had no fun that I tried to draw some of their outfits during the different arts, you could check them out( maybe I should place this in fanart section...)