Fire escapes need yearly maintenance(908) and 604 is every 5 years as required by the SFBD or San Francisco Building Dept.
Most States have the “Must be operational at all times” requirement in the Code which requires that the owner examine the fire escape constantly and this becomes the “If it ain’t Broke don’t Fix it rule”. Owners will only fix it when a code official sees a Violation. By this time the fire escape might need more than just quick fix. Your fire escape should be maintained ever 1 to 5 years.