It is shown that through careful experimental design and proper monitoring, assessment of the corrosion rate beneath thin-film electrolytes in industrial environments is possible. This paper discusses the various problems associated with performing corrosion rate measurements in these often times transient, thin film environments through the review of several industrial case studies where Linear Polarization Resistance (LPR) techniques were utilized to assist in monitoring corrosion. Keywords: thinfilm, corrosion rate, flue gas, polarization resistance, condensation, corrosion probes, case studies