Some questions and answers from The Knot. Visit http://www.theknot.com for more like this or to ask your own specific questions.
What to do if guests do not RSVP?
Call to see if they're coming. You never know -- maybe they think they sent the response card, but it's really hiding in a pile of mail. If calling is a problem, assume they are coming and make sure there’s food and seats for them. It's better to have extra grub and room than to have neglected guests wondering where to sit!
Should we invite relatives we know won't come?
Yes -- you know you want your relatives to come to your wedding if they can. Don't assume they won't come just because they have to travel. If you'd like someone to be there on your big day, simply send an invite and let them take it from there.
What about inviting co-workers?
You're under no obligation to invite your boss, or anyone for that matter, to your wedding. To avoid any false expectations or hurt feelings, make it known to your coworkers and boss alike that your wedding is going to be limited to family and close friends only. The fact that no one from work is being invited will help everyone, especially your boss, from feeling excluded. It would also be smart to keep workplace wedding talk to a minimum.
Who should be invited to the rehearsal dinner?
It's really up to you. The rehearsal dinner guest list can include just the two of you, your immediate families, the wedding party, and the officiant and his/her spouse. Or it can be a larger event, including all your out-of-town guests (or at least all those who will have already arrived for the wedding). It's a nice gesture to include out-of-towners (especially when the rehearsal dinner is the night before) so that no one is left stranded in their hotel rooms.
When should wedding invitations be sent out?
Ideally, invitations should go out eight weeks before the wedding -- this gives guests plenty of time to clear their schedules and make travel arrangements if they're out-of-towners. If you mail your invites this early, you'll be able to set the reply-by date about three weeks prior to the wedding. That way, you should have plenty of time to get a final head count and make the seating chart before the wedding-week crunch begins. At the very latest, guests should receive their invitation six weeks in advance, and you should receive responses two weeks before the wedding day.