I only keep selected cards if they really feel very special for some reason. Otherwise cards are the kind of thing that gradually accumulate until they take up far more space than you'd ever want to give them.
I've cleared out enough space taken up with old cards to not want to inflict that on myself later, or on whoever gets to go through all my stuff if I die before I run out of space for cards. Seriously, after one family member died we found the get well cards that had been sent to her mother, who died over 20 years previously. She still had every single one of them. Sorting through that house resulted in something north of 25 cubic yards of trash, excluding what I burned.
