That mask over your nose is a filter. It
People with compromised immune systems, or some kind of respiratory illnesses may be harmed through wearing a mask - and have to employ other methods to stay safe. For a normal, healthy person, however, I think it is sufficient to change the mask frequently.
Also, understand - I'm talking about people that have Covid. I agree the earlier blanket mandates were stupid.
I think it's a mistake to think, that when someone is coughing or sneezing, that those drops fly towards the other person's mouth like a homing missile or a torpedo.
Instead of laminar flow, think of turbulent flow.
The mask is like a chain link face, which can trap pebbles at a beach.
It's not a perfect defense, but it substantially increases your odds.