I don’t want to threadjack but Rus, my 3 kids are all up one grade. But I homeschool them so I guess it’s not as complicated of a situation (depending on how you look at it) as in public school.
As for changing schools, my family moved when I was 11 and 17. I’m not going to sugarcoat; it sucked both times in different ways. There are 5 kids in my family and I saw how it affected us all differently (the 2nd move I was the only one affected). Like someone else said, it really depends on the child and the situation. I think changing schools can be a good thing if the child is having problems at the current school. For example, my brother struggled in school and when we moved, my parents decided to have him repeat the 8th grade. Since it was a new school in a totally different state, no one knew and it turned out to be the best thing that happened to him both academically and socially. Personally I wouldn’t do it if my child was doing really well at a particular school and it could be avoided.