Recertification is dependent upon the manufacturer. Some manufacturers do not require recertification or periodic factory authorized service. Other manufacturers typically suggest a recertification every 1-2 years. The ANSI/ASSE Z359.14 standard published in 2012 includes a specific schedule as a normative part of the standard. In 2014, the schedule was revised to be optional due to complaints registered by a small number of manufacturers and end-users.