When negotiating for members, unions are allowed to only negotiate for wages, benefits and working conditions. Many teachers use those wages to pay for school supplies which the districts do not supply, because of budget cuts, to educate the students. They use those benefits, such as health care and sick leave, to stay well and to recover from the illnesses that students bring with them and infect their fellow students and their teachers. Working conditions include the number of students per class room, class size. Did you know 15 is considered ideal but is seldom seen. They also cover the number of classroom aides to assist the teachers with students with special needs. Based on their education, many teachers could make far more in the private world than teaching.