After operating pressurized water reactor (PWR) steam generators in U.S. nuclear plants during the past 33 yr and plugging thousands of tubes and replacing numerous steam generators at immense costs, utility and steam generator designers are now confident that they can design, build, and operate PWR steam generators successfully. Deployment of liquid-metal fast breeder reactors (LMFBRs) will likely follow the same scenario if long-term testing is not performed and development completed prior to commercial deployment. A case is made for endurance testing of steam generators to be used in future LMFBRs.