Okay, so I had a phone interview and I have an interview for a PhD program in Photonics this week. I know first impressions matter, so I want to know what to wear. I have a campus tour, lunch with the professor, a tour of the facilities etc. Online I'm seeing every suggestion from "not dirty clothes" to "a suit and tie". Any advice from this physics specific group? What did you wear? What do you expect those you interview to wear? Many thanks!