All thank you notes should be written within three months of the receipt of the gift. The notes don't have to be lengthy, but they should mention the gift by name, and refer to how you will use it: "Thank you very much for the champagne flutes! Michael and I will think of you every time we use them. We hope you'll be our dinner guest sometime soon." When writing about a monetary gift, you do not need to mention the amount, but do mention what you plan to do with it: "Thank you both for your generous wedding gift. Michael and I are saving for a house, and you have helped bring us closer to that goal."
Here is the list of all people who should receive a handwritten thank you note:
Anyone who gives you an engagement, shower or wedding gift, even if you have thanked them in person. Individual notes should be written to people who contributed to a group gift.
A personal note attached to your attendants' gifts will let them know how much you appreciated their efforts and support.
Anyone who hosted a party or shower for you.
Suppliers and vendors who exceeded your expectations.