Instruct: Classify Amazon reviews into positive or negative sentiment
Query: new one every year

I've owned several of these, and they always need to be replaced after about a year. Generally I retire them when the heating element goes out of control and starts overheating to the point of burning. The slow decline takes several months. First one of the 3 heat levels will stop working, and I will only be able to operate it on the other two levels, and finally I'll only be able to operate it on the last (highest and hottest) level. Then I will notice it getting WAY too hot for comfort. The pad becomes a burned color. A minor but consistent irritant also is that the cover is very skimpy, needlessly so, and his held on by a very feeble snap. The cover immediately falls off every time I use it. I recommend this product for a flame-resistant immobile person.