I bought this last fall and started using it right away. It was exactly what I wanted. In the spring I used it again and everything was fine. I used it this fall and it was fine on the first 4 tires but didn't show a reading on the spare tire. I went back to the first 4 tires and the reading drops to zero as soon as you remove the gauge. I think I'll go back to the old stable reader. I've tried digital readers before and they've all failed after a year or so. I still have my 30 year old e-reader.