[veemjeem]

you can reuse n95s, nurses do it all the time. let them sit near a sunny window, off-smells will dissipate in a day. each mask is good for around 8 hours of continuous usage, but it's likely that the mask becomes too soiled before the electrostatic charge is neutralized.

[TylerE]

In a non-healthcare setting the lifespan of an N95 is way longer than 8 hours perhaps 30-40.

Generally the idea is to get a new one when it becomes noticeably harder to breath.

Generally for COVID use, as opposed to say, construction, I find the mask will physically fail (e.g strap breaks or stretches too much, nose foam detaches) before the filter media is close to being used up.