My mother sends a Christmas card to me ('to my daughter') and one to each of my DSs ('to my grandson'), one to me and DP ('to my daughter and her fiance') and then one to all of us (usually one like 'to the family')
My brother is 16 and still lives at home so she buys his and makes him write them too so we also get 2 x 'nephew', one 'sister' and one 'sister and DP' (still pains my mum its DP and DH!)
So from the 2 of them, the 4 of us get 9 cards!
And she expects the same back so 2 x grandma, 2 x uncle, 1 x mum, 1 x brother and 1 x the family so I have to buy 7 cards for 2 people to cover all relationships...please tell me this is not he 'done' thing and I am indeed being not being unreasonable, its cost me a fortune in postage alone this year!