Should I address my landlord/landlady as Herr/Frau+Famlile name or as given names? I thought for a formal and business relationship, you should always use 'Sie' and Herr/Frau. And that is what I do when contact landlords and landladies in WG-gesucht. Current I am going to sign a contract with one, and he starts the emails with 'Hi' + my given name. Should I also call him by his given name? Usually, we talk in English, if we are going to talk in German later, should I use du as well? He is relatively young among landlords. Is it the fashion among the younger generation? Or is it because he rents rooms to college students only? I learnt one rule in the textbook that 'Students usually call each other du'. He is very likely to be or used to be a college student himself as well.