Previous chapters presented and partially analyzed factors limiting the accuracy of EMF standards with dipole antennas, whip antennas, loop antennas, directional antennas, and guided waves. Several examples of accuracy estimations of the standards designed and used by the authors were introduced. Now we will try to present several methods that may be used when an estimation of separate factors limiting accuracy may be evaluated and the ways an estimation of a standard's accuracy may be verified. Although the role of the factors may be discussed without an unequivocal answer, intensive work has been done toward their full identification and evaluation. The first step here is the continuous care of the power sources, meters, directional couplers, and other auxiliary equipment. These devices must be stored in appropriate conditions that ensure their protection against electrical and mechanical failures, corrosion, and other unwanted damage that can degrade their electrical properties. Apart from this, the equipment should be subject to periodic testing and calibration. Some components, for instance, thermocouple heads or the diode detectors, may be tested and calibrated directly by their users. However, the most important devices must be calibrated in a specialized laboratory, for example, by the manufacturer or other authorized institution (as, for instance, with data shown in Tables 7.1a, 7.1b, and 7.2). Final results of the approaches, i.e., the accuracy of a standard, may be proven by a comparison with other devices. The comparisons may be performed within a single lab, with different standardization methods, or, much better, cross-comparison standards in different labs. The latter may be especially helpful in eliminating permanent errors that could neither be observed nor taken into account in a lab where they frequently appear in its routine measurements.