With the increased public focus on PFAS contamination, foam system conversions from AFFF to SFFF began in earnest in the US in 2019 and have not slowed since. Early conversions were hampered by lack of available products, lack of testing, lack of listing, and no mention of SFFF in the codes and standards. In the last six years, the industry has matured to provide more products and better guidance, but there are still lessons being learned on every foam system conversion. This presentation will examine many of these lessons: the conversion process, options that can make a new system more user-friendly, planning for impairments during the conversion, decontamination of existing PFAS, acceptance testing, and other lessons learned through hard experience. The presentation will also look at some of the challenges that still remain in the foam industry as we move to new foam products.