My daughter, who rents an apartment in Philly, recently told me how her refrigerated food kept spoiling faster than she thought it should. Eventually she realized that her fridge wasn’t maintaining the appropriate temperature. A quick call to maintenance and another appliance was delivered. I keep one of these cheap thermometers in our older, spare fridge. I check both the fridge and freezer temp regularly. One surprising thing I learned is how drastically a bowl of warm leftovers can raise the overall temperature. Now I am especially careful to cool food completely before I put it in.