At Astef, the earlier the better. I confirmed my wedding date in December, sent packets out right after New Years. My wedding is on November 18, so I had my travel agent put together 2 packages (3 or 4 nights). If they booked before March, they stayed below $1200. After mid-March, airfare slowly creaped up and now its about $1675 at the cheapest, $1900 at the highest. I would suggest at least 8-12 months in advance. It gives everyone time to space out payment options. Just my 2 cents....