An example - a couple I know had a break-up but carried on living together. Should I send them a Christmas card each or one addressed to both?
Another one. Suppose I have a friend called Chloe whom I've known for 20 years. She has a long term partner called Roger whom I hardly know, I've only met once and spoken on the phone to him a couple of times. They live apart for 8 months of the year because he works in another country, should I address my Christmas card to "Chloe" or "Chloe and Roger"?