It can really depend on the kid. We pulled DS9 out of school towards the end of the school year, so we used the summer for deschooling. I'm not sure it was enough, and in retrospect I would have started our school year more slowly. His school experience, especially that final year, was pretty bad, and I still feel he is recovering, nearly 2 years later.
DD7, on the other hand, only needed a long weekend before she was ready to dive into homeschooling earlier this year. (Although technically she, too, had the summer for deschooling, as she was only in school for about a week before she left). Her school experience had been much more positive.
Since we were all new to homeschooling, I wanted to talk to DS about the different styles of homeschooling and different options for some subjects. When he first left school, he was unwilling to discuss this with me at all (and was quite belligerent, in fact). By the end of the summer (about 3 months later), he was more open to talking about homeschooling. I know I wouldn't have been able to do anything "formal" before that point.
