I first got this mask last summer when i was working as a rough neck on an oil rig, with it on you cant smell anything. When i left i kept it and used it for restoring a 19 foot rowing scull i was doing allot of fiberglass and painting. Ive worn it nearly all day straight allot, its comfortable and i would only replace the filters when it became difficult to breath. The higher the humidity you are around the shorter amount of time the filters will last. overall definitely worth the $$