We are mailing ours out at the beginning of June. Our hotel block requires guests to book by July 2nd, and we need to make sure guests are able to take advantage of that opportunity. Because of the Labor Day weekend, and beach location of our wedding, we want to be very cognizant of the guests' need in terms of both travel and accommodations.
We are getting married on Sept 2 and we send our invitations at the end of April but we also didn't send any save the dates. I think people typically plan their memorial day and July 4 plans before Labor Day but because it's a holiday weekend I would send them earlier, especially if you haven't sent STDs.
Our wedding is 9/29, and I'm thinking we will send them end of June or beginning of July with an RSVP date of 9/8 since nobody needs a headcount from us until one to two weeks before. I feel like most people will forget if I send them any sooner.