Hi ladies! I am wondering about this as well. We are getting married in Jamaica in May 2015. I sent STD out in January of this year so that was like 16mos ahead of the wedding. I wanted to give everyone plenty of time to plan. My mom is a travel agent and she is handling all the booking/deposits of the rooms so she keeps me posted on who has contacted her and what not.
I am still not sure when to send formal invitations. The final payment will be due Feb 1st, 2015. I am not sure when to send them. I do have all the payment/deposit deadlines on our wedding website which I included on the STD so everyone is aware of that. I was thinking of just sending invites out in Dec or Jan since we will pretty much already know who is coming by then and that's still 5 months before the wedding. We are also going to have an AHR and not sure when to send those invites, I am sending those separate than the destination invitations.