I seem to have inherited my mother's compulsion for keeping greeting cards. You know, the stacks of Happy Birthday or <insert Winter holiday here> cards that people send. When sufficient time has past, and one is tidying up, I carefully pack the cards away in a manila envelope, labeled with the occasion, and tuck them away for later enjoyment. Except I never do. I just don't look at them again. They are lovely, and many of them are quite expensive ($7 for a greeting card, oh my!) and I feel just awful putting them in the recycling, but as time passes, the collection of Greeting Cards Past is growing. What is the proper thing to do with them, once you've noted the address of the sender, added them to your list for next year, and it is time to put them away?
Dear Card Collector:
This may come as a shock, but the most Perfectly Proper thing to do with a greeting card after you've received it is whatever you choose. If you wish to save them, save them. But if, as you have observed, you save them for no purpose, then there's nothing prohibiting you from tossing them out. This is especially true of greeting cards in which the writers have written only their names and/or a basic greeting. As long as you've updated the address in your address book, toss out the cards and any Guilty Feelings you might harbor about tossing them out.
To assuage those Guilty Feelings, though, you could bundle them off to St. Jude's Ranch for Children, which has a recycled card program to support their programs and services for abused, neglected and homeless children, young adults and families.
There are those, though, who use greeting cards to share special stories, memories, or offer lengthier expressions of their good wishes for you, and these you might wish to keep as a record of your relationship with that person.
One criterion might be whether or not your biographer would find it useful in writing your biography. Etiquetteer has never quite gotten over the footnote in Richard Buckle's definitive biography of Serge Diaghilev. It seems the composer Igor Stravinsky never threw away a letter, and kept a copy of every letter he ever sent (more difficult in those days before copiers). "Biographers can only be grateful," wrote Buckle.