The invitations have been sent and now it’s the struggle for finalizing the guest list. Unfortunately, we live in a society where formal events and rsvp’s are not the norm. Your friends and family will “assume” you know that of course THEY are attending. tell my brides that this will be the “worst” part of the planning but realize that it happens to everyone.
As you begin calling those who did not respond, you will run into a handful of guests who cannot commit one way or the other (whether they are battling an illness, etc). When you submit your final guest count to your caterer and reception venue, be honest with the number of guests that are still “tbd’s” as I call them. Hopefully at the time of contract, you have negotiated a percent of “overage” the venue will prepare for.
If you have assigned seating, I suggest allowing 3-5% over your final guest count. Open seating is a bit trickier…since people do not like to fill the tables you will need a minimum of 2-3 open tables (for an average wedding of 200 guests). Communicate with your reception venue where the open seats/tables are for those “surprise” guests.
Note that this affects the number of favors, centerpieces and rented chairs/linens. A wedding planner will help you prepare for this in advance.