Crash Course in RSVP Etiquette

This is a topic very near and dear to my heart right now... and I must admit that I have not always been stellar at this myself... but I am all about sharing knowledge--especially if the knowledge can be helpful or edifying or enhance someone's quality of life. (In the case of the RSVP, it can enhance your life, and that of your host who has so graciously invited you to an event. )

RSVP is a French acronym that stands for "Respondez S'il Vous Plait" which translates in English as "Respond Please". It is used for formal, or even casual events where a headcount is significant to a host providing food, gifts, or just to determine space requirements.

Usually an RSVP will have a deadline that can be anywhere from a few days to a few weeks before the event. Very Formal invitations will include an RSVP card (or sometimes called response card) with a self-addressed stamped envelope for you to send in the mail. Often response cards will have a line with a M that looks like:
M________________
use the M as the first letter in Mr./Ms and then fill in your name. Response cards may also request a number of guests attending, be sure to fill that portion out and correctly as well (see directions below.) It does your hostess little good to recieve a response card back with one name and no number attending, when she sent the invite to a family of four. Be sure to fill things out entirely so your hostess doesn't have to go to the extra effort to track you down and find out the missing info.
Less formal invitations may include a line on the invite that says RSVP then provides a phone number, email, or instructions on how or who to RSVP to.
If the invitation says "Regrets Only", you only need to RSVP if you cannot attend the event. Otherwise, the host has already counted you in!

SO! You have your invite in your hand, and it is addressed to Mr. and Mrs. John Doe, and it has a respond deadline of May 1...
First of all, read the ENTIRE inivtation and RSVP card carefully. There are a couple of things you need to look for:
1) The date and time of the event. This seems obvious, but if you skim the invite you might miss out of detials, like the specific time of the event... go ahead and jot it on your calendar or check it against your schedule. Paying attention to all the details can save you some greif and embarrasment later.
2) Method to rsvp. Do you have a card to send in, number to call, email address or website to use? If for some reason you are unable to RSVP by the means specified (i.e. online RSVP and you don't have access to a computer...) notify the host by some other means as soon as you can to let them know of your intentions to accept or decline their invitation.
3) RSVP deadline. Note the deadline and do everything in your power to respond by that deadline. Write the deadline in your calendar/planner as well, put the invite or rsvp card somewhere it will not be lost or buried, or just deal with it while it is still in your hand-- mark and send in the card, make the call or send the email right then... done and out of your way!
4) Who the invitation is addressed to. Say for instance the invite is addressed to Mr. and Mrs John Doe, you cannot assume that little Jimmy and Joey are invited as well, in this case only the two guests listed are invited. If the invitation is addressed to Mr. and Mrs. John Doe and Family, or The Doe Family, Jimmy and Joey are welcome to come! If the invitation is addressed to two people, do not assume you can bring your family of 6, your nieghbors, and your neice. Likewise, if Mr. Doe is unable to attend, but Mrs. Doe is attending, she should not assume she can bring her sister with her 'in his place'. RSVP only for the people who are invited by the host. When in doubt it is always better to ask than to assume, (A note or call to your host saying, "We were unclear whether or not it would be appropriate for us to bring our children (or, a guest) to this event," But be prepared and be gracious should your host say no.) However, by asking, note your intentions and be sure it is becuase the invitation was unclear, and not because you are guilting your gracious host into adding 3 more people to the list that they had not invited.

Should you RSVP that you will attend an event you should attend. Only a matter of serious illness or death should keep you away. It's very rude to accept an invitation and then fail to show up, well, and it's very poor ettiquette.
Should you mistakingly fail to RSVP for an event, you cannot decide you would like to attend AFTER the deadline. You should still inform your host you recieved their invitation but will not be attending. Do not fail to RSVP and still plan to attend or show up at the event.

Remember that your host invited you because they would like you there! You should feel honored by their invitation and should in turn do everything in your power to make things easier on your host. So be sure to RSVP correctly and in a timely manner... your host will SO appreciate your effort and etiquette! :)