Materials selection for any oil and gas equipment, but specifically in wells, tend to focus on the nature and characteristic of the producing environments, or injected fluids if dealing with an injector well. They benefit from greater appreciation on the uncertainty range, in terms of volumes, pressure, temperature and concentration of corrodents since it forms the basis of the business case to drill a new well. There is no robust industry-wide materials selection standards, besides that of the sour limitation of ISO 15156, and Operators are therefore relying on their internal standards, if available, or recommendations from equipment manufacturers or suppliers to select the most appropriate OCTG for that given “worst case” environment. This paper describes several wells completion failures that are attributed to temporary internal or external exposures, at times in wells that were not even cleaned up from the initial completion brine. The events that led to extensive internal corrosion of N08535 tubing and cracking of 13Cr-110 ksi (13-5-2 grades per ISO 13680) are described with the aim to bring higher awareness to the Operators that due diligence of materials selection should not be limited to the primary fluids that are to be transported.