You should send save-the-date cards to all of your intended guests when either of these circumstances fit your situation. Even friends and family members who you already know will attend should be sent a card.
Another well received way is to print a mini calendar page with a 3-hole punch so your friends can attach it to their own calendars. Of course, you would have to circle or decorate the day that belongs to you.
What you should do – Since this will be your first written contact with most of your guests, it’s important that they make a good first impression. Make sure that you spell each guest’s name correctly. If you are unsure about the spelling of someone’s name, look it up or contact someone reliable.
Planning and Sending – Once you know all of the basic details about your wedding plans, place your order with your stationer. As with invitations, having these cards printed can take up to several weeks, so give your stationer plenty of time. You can mail these cards out up to six months before the wedding date. Save-the-date cards can be designed to match the rest of your wedding stationery and ordered at the same time, or they can have a completely different look.
Timing Is Everything – Wedding invitations are generally mailed out six to eight weeks prior to the event, but save the date cards should be sent out four to six months ahead of time. This way, guests will be able to shop around for transportation, schedule a convenient flight, reserve a hotel room, and make other necessary arrangements. Major events are exciting social gatherings that everyone will want to attend, both family and friends from near and far. Sending them out well enough in advance makes it far more likely that all of your guests will be able to attend.