We RFI-test to find problems and repair a few rooms. We feel bad when a good running MRI can’t image because a shield has failed to the point it can’t be repaired and must be replaced. There is no good reason a 30 to 80 thousand dollar shield shouldn’t out-live the MRI in it. The truth is, some companies made better shields in the 1980′s than they do now, and I suggest we get an industry wide focus on quality and longer shield life. There are some really good shielding companies that consistently build good, long-lasting shields. I know who they are, because I test them.