I just don't get the 'thank you card' fetish on MN.
It's a waste of paper, stamps and everything in this day and age to keep thanking people via card, when you could do something much nicer, which is personally call them, thank them in person or email/text a quick note.
There's nothing courteous about clogging up people's houses with cards, and I never keep one unless it has a nice baby picture on it and even then it may go in the bin after a period of time.
It's like thank you cards for children's birthday presents, totally unnecessary if you have looked the person in the eye and thanked them.
The only time I would send a thank you is if for some reason I was sent something and I couldn't see/talk to the person for ages, but that never happens as I see/talk to most of my friends through some medium within a reasonable time frame.
I also hardly ever receive thank you cards except for wedding gifts (and I really don't care if I get them either). So, I'm guessing a lot of people are like me.
Once I hand over the gift I think 'job done' and move on. I don't want recognition days or weeks later like I did some amazing thing.