I would like to know what is the expiration on sending a belated birthday card? In other words when does it become “tacky” to send one? When you are a week late? two weeks? is a month ok?
I forgot a birthday on Aug 16th and 22nd. I wonder if I should just forget about it.
Does it matter “who” the belated card is going to? Is it acceptable for family but not friends to receive one really late?
I think a belated birthday card should go out no more then a couple days after the birthday. That way they may think that you at least thought about it on there birthday, bought it and sent it out shortly after. Any later then it seems like to small of a gesture for taking to so long to remember…
I’d write them both a letter. To apologize and to just be a letter. People still like getting letters. I think the quantity and qaulity would help show your sincerity.
Sigh. I type by ear and I just woke up. How embarassing.
I do not think there is a statute of limitations for this. But it depends on the type of relationship you have with the birthday boy or girl. And whether or not a check will be enclosed! 
Strange enough, I rarely congratulate people on time. Usually I think about their birthdays a few days before it and a few days after it… I then pick up the phone and wish them a belated birthday, 1-5 days afterwards.
Cards should be sent out in advance anyway, as the mail delivery takes time.