We have since the beginning of January (in fact we have several, one in the hallway, one in the bedroom of our son, we would eventually have three more: the remaining two bedrooms and living room) so far we do not need. I currently have the flu so stuffy nose, and I was cooking chicken broth, except that fatigue helping I have not been checking in time, the stock suddenly evaporated, and it started smoking, and the detector corridor has tripped, this is was not at the stage of black burned, but burned brown stage, the stove is located about 8m of the detector.