Don't let this Old School etiquette rule trip you up.

Don't let this Old School etiquette rule trip you up.

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Southern women hold this truth to be self-evident: You should always RSVP, particularly to such formal affairs as wedding receptions. When people are kind enough to invite you to a social event, you should be considerate enough to let them know whether you’re coming so they’ll know how much food to buy, how many places to set, and so on. (If you’re iffy, call the host well in advance and let her know your situation.)

But what about a combined wedding-and-reception invitation with no RSVP card? That’s Old School. The host assumes that you’ll send a handwritten RSVP note on your personal stationery to let her know whether you’ll be attending. (Tip: A wedding response card is not the time to break out the SEC-themed stationery. Etiquette experts recommend a conservative notecard in ivory or ecru. White is also acceptable . . . sort of.)

Is the ecru treatment of a formal RSVP necessary for that backyard barbecue your neighbor e-vited you to? Unless you’re Queen Elizabeth, no. An email or phone response is fine.

The “RSVP” abbreviation in all of its forms (R.S.V.P, Rsvp) has been around so long that many of us don’t know what it actually stands for: Répondez, s’il vous plait, which is French for “Please reply.”

Granted, the rules of etiquette have relaxed over the years. (Amy Vanderbilt’s epic guide is fascinating to read, but it might make you reluctant to leave your house for fear of a faux pas lurking around every corner.) Even in the more casual, modern South, however, there are some traditions and social “musts” that endure, like please and thank you; yes ma’am and no ma’am; “Y’all come on in” and “Who wants coffee?” The rules of etiquette that we follow in order to show respect and consideration for each other—those will never go out of style.

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