If you already have N95's then I would invest my money in something else. A filter-type NBC mask has to be refitted every year. Some types do not work with any facial hair. I was issued my first in 1983 for my riot bag. It has never been used outside of training. They DO NOT work in O2 depleted environments. If you are concerned about flu, good hygene and a box of N95's (and common sense) should get you through. If you live or work in a building over five stories, and it does not have fire sprinklers, then I might consider an escape hood with filter, once again knowing that it does not work in an O2 depleted environment, but may buy you some escape time in case of fire.