The ph probe on my bluelabs combo meter lasted over 2 years and was still accurate. The Ph button got a little crack on it from so much wear(they have since updated the buttons). I walked into my closest authorized dealer (which I didn't buy it from) and walked out with a brand new updated unit with a new ph probe. I have a milwaukee digital automatic ph adjuster and my bluelabs knows what the ph really is 3 minutes before the milwaukee. My bluelabs truncheon is a great backup and has been in service for over 3 years. I like being able to check my ph and ppm meters against each other and the blue labs warranty is awesome. Buy once , cry once.