Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Numbers are rubbing off

I purchased this thermometer 4 months ago for making homemade yogurt. The problem is that the numbers are rubbing off. I never put this in the dishwasher but hand wash only. I am very careful with it and I don't use it for heat above 180 F (although it is suppose to be fine with much hotter temps). A thermometer is only good when you can read the temperature, and it is getting harder to do this. Already several numbers are completely gone. Now I am looking for another thermometer after only 4 months.