If people live in the same house, are you just sending one invite? What about if they'll have moved out by the time you get married? For example my Aunt, Uncle and 2 cousins (16 and 18) live together. My 18 year old cousin is moving out to go to university. Would I send one invite for all 4 of them? Or do I send a separate invite for my 18 year old cousin since she'll be living elsewhere on the actual day?
We invited couples on one invitation and any other adults in the same household got their own invitation. In the case of a 16 and an 18 year old we'd probably have sent them both a seperate one so three in total. No need to do this though!