(1) A person may be excused from jury service by the court upon a showing of undue hardship, public necessity, or that the person is incapable of jury service. The excused period may be for any period for which the grounds exist.
(2) The grounds for excusal from jury service shall be shown by affidavit, sworn testimony, or other competent evidence.
(3) The court may postpone jury service upon a showing of good cause.