Probably the most contentious aspect of the COVID-19 pandemic has been PPE for staff. And within that, the most contentious aspect of PPE has been respiratory protection when caring for patients with confirmed or suspected COVID-19: to FFP or not to FFP? I have been involved in a review of international guidelines to identify variation and track the changes in the guidelines over time. Things have changed as evidence has emerged, but international guidelines still disagree on where and when FFP respirators should be worn when caring for patients with suspected or confirmed COVID-19. The review also tracked variation and changes in recommendations about what should be considered an AGP.