Haven't worn one and don't intend to wear one.
If social distancing is maintained and unless somebody spits in my eye in a supermarket, I struggle to believe there's much risk.
I saw a woman at a distance in a field over the weekend walking her dog - other than me, there wasn't a soul about - I then saw her get into her car and drive-off. She had a face mask on, and whilst I'm no expert, I can confidently predict the risk of her catching the virus in an all but empty field and then her car, must be so close to zero to make the number negligible.