Guidelines for the following are included in the standard: insulating liquid maintenance and diagnostics, liquid reclamation, testing methods for the determination of remaining insulation (paper) life, and upgrades of auxiliary equipment such as bushings, gauges, de-energized tap changers (DETCs), load tap changers (LTCs) (where applicable), and coil re-clamping. The goal of this guide is to assist the user in extending the useful life of a transformer.