(a) Authority for Appointment. Unless a statute provides otherwise, a court may appoint a master only to:(1) perform duties consented to by the parties;(2) hold trial proceedings and make or recommend findings of fact on issues to be decided by the court without a jury if appointment is warranted by (A) some exceptional condition, or(B) the need to perform an accounting or resolve a difficult computation of damages; or(3) address pretrial and post-trial matters that cannot be addressed effectively and timely by an available district judge.(b) Disqualification. A master must not have a relationship to the parties, counsel, action, or court that would require disqualification of a judge, unless the parties consent with the court's approval to appointment of a particular person after disclosure of any potential grounds for disqualification.(c) Expense. In appointing a master, the court must consider the fairness of imposing the likely expenses on the parties and must protect against unreasonable expense or delay.