I'll give this a shot:
- Food & Wine runs from the beginning of October through the middle of November, so that time frame is busy.
- Early December books up even faster because of low point costs, great holiday decorations and lovely weather.
- The holidays are always busy, so count on a full house Thanksgiving week thru the weekend, and of course Christmas through the New Years holiday.
- Hilton Head is extremely busy during the summer months, very difficult to get a summer ressie without the 11 month advantage.
"Busy" other times is dependent on your meaning.
DVC rooms are always pretty full, but the above times definitely fill up in the 11 month window. Other times of the year get pretty busy, may have wiggle room to get in at the 7 month window, but maybe not if you are talking, for instance, a 3 month window.
Someone elsa can probably add some thoughts to this.