An initial evaluation must be conducted prior to a student being considered for special education and related services. Unless the parents and the school district agree otherwise, a re-evaluation must be conducted at least every three years for special education students, but may not occur more than once  a year.  A re-evaluation must be conducted when the District believes it is warranted and when requested by  the student’s parents or teacher. [20 U.S.C. Sec. 1414(a)(2); 34 C.F.R. Sec. 300.303.]