I agree with everyone's comments - we only send postcards to my mother and sister-in-law nowadays. My sister sees the card my mother gets. Once or twice I have sent one to the office, if the place we are visiting has some relevance to work.
But we used to go away with a pack of ready-printed address labels - nearly as many as the Christmas card list.
At one point, when the kids were small, you could get address labels which were the size of a postcard, which I pre-printed before going away. We then took a 12 exposure film of us on the beach or at a famous place of interest, had several copies made locally and stuck the stickers on the back of them.
We also sent them to ourselves, so there was one waiting for us when we got back home.
As someone has said, stamps are difficult to come by these days, especially in an unfamiliar country. And if you see a letter box, you either forget to post the cards, or haven't got them with you. Fortunately you can leave post at the hotel reception desk or camp site office, but it may take a while before they actually get posted!