My son is starting 1st grade this week at his third elementary school.
We started off last summer thinking he'd go to the neighborhood school, because we were waitlisted at the magnet to which we applied. Then, about 1 week before the 1st day, we learn he got into the magnet. So he started K there, after getting used to the idea of the neighborhood school. Then halfway through the year we moved to a different state, so in January he started the second half of K at a new school, and did pretty well after about 1 week of adjustment.
Over this summer we moved again (from an apt to house) and are in a new district -- we would have tried to stay at the same school but the neighborhood was just too out of our price range.
He's nervous about starting school, but is shy by nature. Today I saw the downside of switching schools - when we went to meet the teacher, there were a few kids who saw that their seat is next to a friend they made in K, and one pair of old friends who were already playging together, oblivious to everyone else. I'm worried my already shy son is going to feel left out when he see that some of the kids already know each other and are good friends, but I'm hopefull that the teacher will help faciliate mixing up the group so everyone gets a chance to sit together/play together.
That said, I'm not thrilled with the school so far, and am toying with the idea of applying to a magnet school, so yet another change looms for him...