The FDA now has a policy to review all guidance documents every 10 years to identify if there are guidance documents that need to be updated. Since there are guidance documents dating all the way back to the 1980s, they are currently playing catch-up. They are doing retrospective reviews of the following years in 2024: 1994, 2004, and 2014. They also publish a list of guidance documents that are planned for revision each year. The list is divided into 4 parts: 1) A-list final guidance, 2) B-list final guidance, 3) A-list draft guidance, and 4) B-list draft guidance. Sometimes the FDA decides not to update a guidance, because there is no urgent need. Other documents get updated as frequently as once per year. Pilot programs that are new fall into the category of needing updates frequently, such as the breakthrough program.