When a guardian or conservator is appointed, the court may, with the consent of the guardian or conservator, insert in the order of appointment conditions not otherwise obligatory providing for the care and custody of the property of the ward or conservatee. Any such conditions shall be included in the letters. The performance of such conditions is a part of the duties of the guardian or conservator for the faithful performance of which the guardian or conservator and the sureties on the bond are responsible.