Most states specify in their state constitutions the terms of office for judges. The practice goes back, at least for higher level courts, to the Revolution and/or statehood; a complaint was that a judge who displeased the Crown or later legislature might find their term of office reduced to zero. In Tennessee, this takes the form of Article VI, Section 4 for trial judges
The Judges of the Circuit and Chancery Courts, and of other Inferior Courts, shall be elected by the qualified voters of the district or circuit to which they are to be assigned. Every judge of such courts shall be thirty years of age, and shall before his election, have been a resident of the state for five years, and of the circuit or district one year. His term of service shall be eight years.
HJR 91 of 2015, however, would delete that last sentence and allow the legislature to set any term it wished.
The term of service shall be set by the general assembly.
HJR 91 has been filed in the House but not yet assigned to a committee.