Invitations, no question about it. Until a couple of years ago I had never even heard of a "save the date".
Wedding invites go out 6-8 weeks in advance. 10 at the very earliest. You can send Save the Dates out at 6-9 months with travel info.
Depends on the occassion. At least two weeks for most things. Weddings or Family reunions, especially with out of town guests, a MINIMUM of two months in advance, and more if foreign guests or people you know are very stingently committed at work. For these people, an advance note that a formal invitation is forthcoming may be in order.
You can have a printing company do them; you can do your wedding invitations on your computer and print them out; or, handwritten is very personal and a delight. Remember to put your return address on the envelope that your guests will be replying too along with a stamp in the upper right hand corner.
No, dates do not have to give a gift to the wedding couple. Your date does.
You can view statistics of the most common wedding dates in a few places. The website AppilyWed offers a list of the 5 most common wedding dates. Wedding Industry Statistics also offers a wide range of wedding related statistics including information on the most common wedding dates.
I Dream of Nene The Wedding - 2013 The Wedding was released on: USA: 27 October 2013
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Whose Wedding Is It Anyway - 2003 Wedding Warriors was released on: USA: 26 May 2009
Whose Wedding Is It Anyway - 2003 Wedding Survival was released on: USA: 12 July 2010
My Bloody Wedding - 2010 was released on: USA: 2010
The Pigs' Wedding - 1990 was released on: USA: 1990
The Wedding Planner - 2012 was released on: USA: 2012