I think it's really personal preference, but here is what we are doing.
We have 2 lists of people, 1 of people who we think are going to attend, and 1 of people that we know will not attend due to outside circumstances (jobless, going through radiation, etc.). I am sending out STD's, in the next 2 weeks to the
first list and they include an 'Intentions' card, which they are asked to send back if they already know they won't be able to make it as we need preliminary numbers for our coordinator. If they respond 'no' on the Intention card, they
don't get a real invitation, therefore freeing up a spot for someone that we couldn't invite.
Then, in February we are sending out our real invitations asking that the RSVP be sent back by April 1st.
Being that we are having a DW, we have to have concrete numbers so that we know where we are budget wise. Plus, our venue has size restrictions, so we are somewhat limited and need to know who is coming sooner rather than later -hence the
intentions card.