As a general rule, a thank-you letter should always be handwritten and sent within a week to ten days of an event or receipt of a present.
Thank Yous for presents
Thank-you letters are necessary to acknowledge presents given for Christmas, christenings, weddings, birthdays and anniversaries. Refer to the present directly and include some details to personalise the tone of the letter.
Remember that in our digital age, a handwritten letter is always appreciated so, for maximum impact, make the effort to write promptly.
children's thank yous
It is appropriate for parents to respond on behalf of their offspring before the child is able to write. The child should write their own, however, as soon as they can. Children should be encouraged to specifically refer to the present in the letter, and make a detailed comment about it ('Thank you for the teddy you gave me for my birthday. I have named him Edward'). An extra sentence of topical news about the child's life adds a personal touch ('For my birthday treat, I am going to the cinema with my friends').
Traditionally, children should always write a thank-you letter for presents, but it is becoming more permissible for children to say thank you in person if the giver is there when the present is actually opened. Much will depend on the expectations of particular families or individuals.
thank yous after an event
When thanking someone after an event, the form of the invitation signals the appropriate format of a thank you. Engraved invitation cards require a formal thank you letter. An at Home card suggests a short letter or note.
Traditionally addressed to the hostess, nowadays letters can be addressed to either the host, hostess or couple as appropriate.
A verbal, telephone or email invitation needs only a telephone call of thanks after the event; telephone and email are interchangeable if all parties use both frequently.
other thank yous
Thank-you letters should also be sent after being a guest in someone else's home, for example after staying for a weekend or Christmas.
Support during a key event or task - bereavement, wedding, reference for a job - should also be acknowledged with a brief letter of thanks.
Nowadays, however, email is generally acceptable for brief and informal thank yous.