I've rarely done out calls so I usually show up in my work clothes.  Which is khakis and a nice shirt/shoes.  Last time I did in call I wore shorts (no holes; khaki) and a button up shirt.  I was barefoot since it was in a beach condo.  It was a very sunny day in the spring and I had the sliding door open so it seemed appropriate.  Of course, I live at the beach so it's pretty standard attire.

If I were traveling and at a hotel and hosted, I'd most likely wear something similar to my work clothes.  Nothing sloppy.