Do we have to invite someone to our wedding if they invited us to theirs?
Nope! There are lots of factors that go into your guest count; the size of your venue, your budget, etc. Your friends who just got married will understand. They went through the exact same process not too long ago. If you feel really bad about it, be honest with them and let them know that you just do not have the space/budget to invite everyone that you wanted to, but that you still value their friendship.
How do we respond to guests who ask to bring an uninvited plus one, child, etc.?
This is a great question and I actually had this happen at my own wedding. Someone crossed out two and wrote six! Handle this on a case by case basis and do not jump to conclusions. Maybe the plus one is a caregiver that needs to help an elderly person get around, or a nursing baby, etc. In our case, it was family that needed to drive an elderly grandmother in from out-of-state. Find out who the plus one is and why it is important for them to attend. If your guest is really trying to get an extra person in that does not need to be there, be honest! Let them know that you have limited space and budget, that the caterer already has your numbers, the seating chart is complete, etc. and because of that, you are unable to allow another person to attend. Most people will understand.
What do we do about guests who have not responded to the invitation by the RSVP deadline?
Just ask. People are busy and they often forget to respond. Or their invitation could have gotten lost in the mail. If the missing RSVP is from your side of the guest list, have your Maid/Matron of Honor or your mom reach out to them. If they are from your fiances side of the guest list, talk to your mother-in-law about reaching out to them.
What is the average ratio of RSVPs to Regrets?
There is no solid formula for this and there are a lot of factors to consider. But, a good rule of thumb is: If most of your guests are local, expect 10% regrets. If you have a lot of out-of-town guests that are not immediate family, expect 20% regrets.
If we have a lot of regrets, is it ok to invite another round of people later on?
Personally, I think this is a bad idea. Someone will get their feelings hurt that they were not in the first round of invitations. There are some exceptions. A sweet lady that I used to work with was literally 1 person over our max guest count. I was bummed. I really wanted to invite her. I explained the situation to her and she understood and was so kind about the whole thing. Two weeks before the wedding, one of our friends had to cancel at the last minute so, I called her and she was delighted to attend! All of that to say, I think it depends on your relationship with the person and how you approach it.
Huge thank you to Kristi of Coco Red Events for her sound advice!