Same thing as if you didn’t wash your underwear. It gets dirty. But with masks, it could have diseases hanging on it. On second thought, your underwear could have diseases hanging on it, too. I’m kinda sorry I answered this question now.
It has been said that the virus only lives for around 24 hours on fabric,so if you rotate some masks I don’t think you will catch it but like @kritiper said it would get smelly and crusty.
I think on one of his Covid Q&A threads, @Caravanfan also said they get saturated, presumably with what we inhale and exhale; which I took to mean that they clog up and their protective function is compromised.
Now, lipstick would be one of the things I would expect to see in low use during this time. Mascara is another story. I sure have seen some stagey eye makeup lately.
@Zaku – It’s not bad once you get used to it. I found that once it’s on, if I just leave it on and not do the on-and-off routine my co-worker does, it’s easier to forget it’s there.
When I get home from work, it feels odd to not put on my mask when I go inside.