When the initial pandemic outbreak occurred over a year ago, it was expected that the COVID-19 coronavirus would be similar to the 2003 SARS coronavirus. That meant many general hygiene measures were needed: handwashing, cleaning of doorknobs and tables, limiting handshakes or other body contact, etc. By mid-2020, it became obvious that transmission by small invisible droplets in the air was a major threat. And now we have solid data that aerosols are the primary mode of infection.
Some folks assume that we wear masks to mainly protect ourselves from viruses in the air. That error was clear when one U.S. senator argued that folks who get vaccinated should be rewarded by not having to wear a mask anymore. But the mask is not just for protecting us alone. Nor is it a 50-50 benefit. The mask is much more important to protect others.