They are required by a court, and the court will vary by the county, township or city where the estate is located, as probate laws vary by jurisdiction. A bond can be required even if the will states that no bond is needed, as it is ultimately left to the judge's discretion. If a fiduciary or executor does not handle the estate according to the will or court orders, a claim can be filed on the bond to ensure the heirs receive the items outlined in the will.