My last T would wear comfortable, professional clothing, mostly neutral colors and usually pants and flats or sandals. Most of the time I didn't notice what she was wearing, which is probably a good thing, but I remember complimenting a blouse or shoes several times. My dietitian was always dressed to the nines and so I usually tried to somewhat dress up and look nice for my appointments. My current T is male, though I've only seen him three times or so. He just wears regular older man clothes, nothing that stand outs but certainly not stylish.