You must wear a Covid mask, but T&Cs apply
Socially acceptable mask-wearing habits tend to vary depending on where — or who — you are
The idea that it takes only 21 days to form a new habit was first introduced into the popular psyche in 1960. The self-help book penned by cosmetic surgeon Dr Maxwell Maltz, Psycho- Cybernetics, A New Way to Get More Living Out of Life, sounds like a sales pitch for a really advanced AI program to be ingested with your breakfast, but is actually the tome responsible for this pervasive notion.
Subsequent research has, however, shown that Maltz's 21 days are a radical underestimation of the time it takes for new habits to form. A better bet is to count on anywhere between 66 and 256 days of consistent practice...