Complex sentence: To some degree the new Praetor had discretion to modify the existing edict of the former Praetor; often the new Praetor would simply adopt and continue the contents of edict he "inherited" from his predecessor.
Split into simpler sentences: To some degree the new Praetor had sufficient discretion to modify the existing Edict of the former Praetor. Many years the new Praetor would simply adopt and so continue the contents of Edict he "inherited" from his predecessor.