I have had really good results from wearing masks. I never really wanted to wear them because I felt stupid. But now I don't care. It beats getting sick. When people stare, my boyfriend yells at them. And I kinda like seeing him as an attack dog. He's usually quiet.
Anyway, I really wear masks more for avoiding pollution, cold air, irritating fumes, car/truck exhaust than germs. When it comes to germs, especially during flu season, I stay away from crowds, or at least stay away from sick people. If I hear someone sniffle, I say, "Are you sick?" And if they say it's an allergy, I say, "Are you absolutely sure?"
If I'm on line at the Supermarket and if I see the checker is sick, I change lanes. Maybe instead of the lane that says "10 items or less", it should say, "Germ free express lane."
Most colds are transfered by touch. So I wash my hands or use Purel if I think I was exposed to anything. And during flu season, I don't love elevators. Flu droplets can hang there for hours. One time, I was leaving work and got into a crowded elevator with a friend. I was debating about whether to use the mask or not. Finally I put on the mask, and my friend thought rather than acting like nothing is unusual, she would say what everyone else was thinking. She turned to the other people in the elevator and announced, "Yep, she's nuts."
I started wearing a mask more often after reading of all my medical records. Almost every single exacerbation (either infections, coughing up blood, pseudomonas flareups, inflamation) that I have had was after an exposure to "bad air." Some examples: a visit on a windy day to a Botanical Gardens, at an air show standing and waiting for a shuttle bus with the engine running, buying tires, smoke of any kind, after a concert in a parking lot after everyone is starting their cars, being exposed to really cold air...Within day or two, major flareups.
I carry a mask with me and whip it out on whenever I encounter anything with strong odors or irritants...if I need something in the detergent aisle, or for instance when I had to board on a plane on the runway with the engine running, or walking by a business with smokers at the door...Okay I'm Michael Jackson.
I am not sure the very thin masks are enough. The mask I like best, one I wore throughout a trip to England (the first time not getting sick on a big trip) was the 3M mask for Latex and Odor Respirator (R95). It is a charcoal mask and it blocks fumes. I get it at Lowes. There is another N95 mask with a vent in it that I also like, but I don't remember the model number (which doesn't really help you).
Also for times, that you don't want to wear a heavy mask, a silk mask is pretty good (very tightly woven fibers.) And lastly, if you really care about looking socially acceptable, you can cover your nose and mouth with a silk scarf.
As for how often do I change them? Every couple of weeks.
