yes DH's family are big on cards. my family aren't. i found the level of card sending quite bizarre. dh does it all though, i have no part in it...birthdays, christmas, anniversaries, easter, new year, halloween (!!) and any and every thing like new job, new home, first day at nursery/school, congratulations on anything and everything, thinking of you for anything and everything.
also every card seems to have to be as 'personal' as possible ie a card for each relation. if MIL can't find the right one she will emboss the card with something appropriate. so on my 30th i got a specific 30th card, and she stuck on it a 'daughter in law' craft sticker thing.
consequently, for his sister at christmas dh dutifully sends off 'sister and brother in law' 'neice' 'cousin' 'cousin' (one from dd and one from ds..to the same 1 cousin) so yes that's 4 cards for 3 people FFS!!!
oh, and finally, all these cards have to posted. we all live in the same town, and we see everyone all the time, but still all cards must be posted 'so you get your card first thing on your birthday.' in practice this means cards arrive about a week before your birthday in case of post delays, so we probably get the card then see the relations twice before it's the birthday.
bloody ridiculous.