Some people save their cards, some toss them away - I still have a good number of Christmas & Birthday cards as mementos but in general have thrown more away than kept.
I also can't be bothered getting too individual with Christmas cards, last year I purchased the Anna Griffin TSV in September and that was a matting & sticking kit. Ended up doing my cards last minute JUST before the international shipping deadline (most of my cards go abroad), and it's usually just about 30-40 cards.
It did get me back into crafting, though, and I almost wish it hadn't as stash shopping has become the death of my budget.