To save yourself time with licking the envelopes, you might consider stickers. You can purchase round stickers with your last initial or a rose or heart. These can be found at the stationery store or where you are purchasing your invitations. Another option is to purchase glue sticks to seal the envelopes.
On the other hand, if you are not sure whether a particular person or couple will be invited to the wedding, don’t send them a save-the-date card. And there is really no reason, and it’s a waste of your precious money, to buy and send these notices when all of your guests live relatively nearby or the wedding will not occur during a busy time of the year.
Rules & Etiquette – Again, few rules apply. The only information you must include is your names and wedding date, although I suggest including location information as well so wedding guests can begin their travel plans. Aim to send save-the-date cards soon after you secure your date and venue, or about 4-6 months prior to your wedding. Remember, everyone who receives a save-the-date also receives an invitation, so have your guest list finalized prior to sending them. You can, however, always add guests later (there is no rule that says everyone must receive a save-the-date card). Although formal replies are not required, you can get preliminary attendance estimates through word-of-mouth.
Save the date cards are miniature announcements that precede actual invitations, and their main use pertains to weddings. They’re informal, concise, and pave the way for the actual invitations, much later on. Since weddings are events that require participation and attendance of the extended families on both sides, it can be quite hairy to ensure that they’re all there. In order to allay any potential problems with attendance, save the date cards are sent from 6 to 9 months in advance, but 12 months is appropriate if the wedding coincides with special holidays and/or it’s a destination wedding.
Your save-the-date can take any size or form. If you decide on mailing cards out, then your cards can be the size of a postcard, or even smaller. Make sure the size does not cramp the wordings together.