growing up on tatooine, luke never got the chance to have a huge variety in his wardrobe. generally, it was one of three tunics, two pants, & a few belts to choose from. & maybe a poncho. but he was always conscious of how he looked & he always strived to make sure that his clothes were never too ragged or too worn.
once he becomes a member of the rebel alliance, his wardrobe expands. a few more tunics, a few more pants, some new jackets & a few flight suits. he asks for leia’s opinion on new clothing & takes her advice on what he could & should add to his closet. it’s not a huge deal, or at least he never makes a huge deal out of it, but making sure that he looks nice makes him feel … nice. it’s something he can control, & it’s also a far cry from the simplicity of his life on tatooine.
once he becomes a jedi, he generally favors long-sleeved, high-necked tunics, & long pants, almost exclusively. occasionally he’ll add a cloak. sometimes he trades those for a flight suit ( space can get cold ), but as he grows stronger in the force he generally uses it to manipulate his body temperature in deep space. he shies away from bright colors that will draw attention to him, favoring darker neutrals.
however, he always looks put together.