With our process, we send out STDs as early as possible with either travel information and pricing or the information of your Travel Account Manager. Your guests are then directed to your TAM and there is a deposit deadline where they will have to commit to. This is done with some time before the actual wedding- how are you supposed to plan accordingly without knowing how many people are attending!? They also need to make sure that the hotel isn't going to be sold out if they wait until last minute. There are almost always last-minute stragglers and we accomodate them as best as possible when the time comes! It is important to us that we let your guests know that this is not a last-minute vacation, it is a wedding so it has to be planned in advance!
Invitations with a Destination Wedding are really just a formality. Since there are deposits, etc. you would know how many people are attending after sendign out the STD. Saying that, we suggest maybe only sending out the formal invitation to guests who have booked (this saves on cost) so they can have it as a keepsake! Many brides are opting out of sending out the formal invitation and just sending out an extra-special save-the-date!