To judge whether your respirator is suitable for continued use, you should monitor its condition closely, [one expert] said. He recommends checking regularly to determine whether the filter layers are visibly wet, soiled or dirty, or the outer edge no longer seals tightly around your face.
“If the respirator is not compromised, you can safely reuse it,” he said. When in doubt, you should toss it and rotate to a new one.
generally, [another expert] said she doesn’t usually re-wear an N95 mask more than five times, and will toss it if it gets dirty or wet.
Some experts say the same respirator can be reused up to a week, if handled and stored properly. However, they say that if you wear it in a high-risk setting like a health care facility, it’s safest to discard it after a day.