The CDC recommends only people who are sick should wear them and medical professionals need them so they can help other people.
Also: you’re probably wearing it wrong. 4/ wired.trib.al/dfaIBmV
Worry about the flu enough to get vaccinated. Many more people die of flu, but that's because more people get it. SARS-CoV-2 is a new virus and its spread is hard to predict. 9/ wired.trib.al/YhrPlU9