For all wedding gifts received prior to the actual ceremony, it is polite to send thank you notes two or three weeks after receiving your gift. This same rule applies to any gifts the couple may have received during an engagement party or bridal shower. Even if you verbally thanked gift-givers at these prior parties, it is still imperative that you follow up with a formal written note of appreciation.
For gifts received on your wedding day or gifted through a registry, it is best to send your thanks within three months. Recipients will understand that you may be busy with other commitments like the honeymoon, updating
legal documents, or moving.