when will you be sending your invites?

I would tell all of those that you definitely want there to keep the date free (you don't need save the dates to do this) and then send invites out Jan/Feb at the earliest.

If you send them too early, I think you run the risk of people forgetting nearer the time (impossible as this sounds)

You might just want to give those that might need to book flights and transport a bit of a heads up around a year to 9 months, and then send the invites out to everyone much nearer the time. This is the beauty of the save the date - it doesn't need to be fancy pants - we made ours like a business card and sent them with the Christmas cards for our September wedding

I made STD Margets and sending them out as we speak. I get married beginning of August, so think I'll send invites out in May x

If there's only a few that need to book flights, you could just tell them the date so they know when to book flights, then send all the invites out together.

We booked flights for my brother's wedding before we received the official invites

Personally think that may be too early, we are getting married in July too. We have sent out save the dates along with hotel info already a few months ago, invites will go out march/april