I have always let the teachers figure it out as far as ability because around here so many parents brag about their kids and the teachers can get overwhelm the first few weeks until they get to know each student a little. On the other hand, if you have disability issues, I would not wait. With my oldest son, I wrote a detailed but focused email with relevant medical and educational background and issues at the beginning of the school year to every teacher. I have been thanked profusely each year at the IEP meeting for the incredible help it provided to the teachers.
