You attended the party but still haven’t sent a gift. How bad is that? Well, under the rules of traditional etiquette, all gifts should be sent before, or delivered at, the celebration, whether it’s a wedding, birthday, shower, or Bar Mitzvah. But before you start declining social invitations because you can’t get your gift act together, remember that the rules are just a loose guide. “It’s never too late to send a gift,” says Letitia Baldrige, author of New Manners for New Times (Scribner’s, $35, www.amazon.com). If you’re only a little late, send an e-mail or telephone as soon as you realize the oversight. “Say, ‘I blew it and let your celebration pass by. A gift is on its way,’” says Leah Ingram, author of Gifts Anytime: How to Find the Perfect Present for Any Occasion (ASJA Press, $17, www.amazon.com). If you’re embarrassingly late, check in with the giftee first. “Even if it’s 10 years late, you can still send the gift — just make sure the recipient is living at the old address,” says Baldrige. In any case, employ a little self-deprecating humor. Says Ingram, “Making fun of your memory makes you seem humble and your feelings more genuine.”