How long do you have to send a thank you after a wedding?

There is no rule that says you must send thank-you cards by a certain date. The law does not care about thank-you cards. Etiquette does. Most wedding planners and etiquette guides suggest sending them within three months of the wedding. That gives you time to catch your breath, sort through gifts, and write something personal. If you received gifts before the wedding, try to thank those guests within a month of receiving the gift. That is a kindness, not a rule. For gifts given on the day, the three-month clock starts after the wedding. If you are very busy, a short, warm card is better than a long, perfect one that never gets sent. You can also send a quick message to say the card is coming. That helps guests feel appreciated while they wait. The key is to be sincere and specific. Mention the gift, how you used it, or what it meant to you. Do not worry about matching the formality of the card to the gift. A handwritten note is always welcome, whatever the value.