Bought two of them at the same time. One is in the family room and the other is in our bedroom. Both myn wife and I have really bad allergies and this has helped tremendously! It is simple to operate. We run them 24 / 7, but you can set them on a timer for less (4 - 6 - 8 hours, I THINK). They're brand new so don't know how long the filters last, but the air particle display shows a high of 119 (when I emptied the paper shredder right next to it!) but normally shows 002 - 006. They started out in the 20's but by that first night had dropped down.