How long do the filters last..........

Well there is not really a straight forward answer. First of all, if you just open them and let them sit on a shelf, there are good for 1 yr. Then you start breathing through it intentionally drawing air through it.........Best thing to do is make sure you store it in a large ZIPLOC bag and only use it when neccessary.

There is only one problem, if you use the glue in your shop during the winter and keep your shop closed up, you should wear it ALL THE TIME.....the fumes linger.