(a) The period for which a credential, as authorized under Section 44250 issued prior to September 1, 1985, is valid shall be as follows:

1. (1) For an internship credential: two years.
2. (2) For a preliminary credential, pending completion of the clear credential program: five years.
3. (3) For a life credential: the life of the holder.

(b) The period for which a credential issued on or after September 1, 1985, as authorized under Section 44250 is valid, shall be as follows:

1. (1) For an internship credential: two years.
2. (2) For a preliminary credential, pending completion of a beginning teacher induction program approved by the commission or the clear credential program: five years.
3. (3) For a clear teaching credential: the life of the holder, if the holder submits an application and fee for renewal every five years and meets all professional fitness requirements under Sections 44339, 44340, and 44341.
4. (4) For a clear services credential: the life of the holder, if the holder submits an application and fee for renewal every five years and meets all professional fitness requirements under Sections 44339, 44340, and 44341.