Originally Posted by phunk

Good question.

These gauges are pretty common to put in engine bays. They have been around a long time. I wont say that I have never seen one go bad in my life, but its definitely not very common.

I have had the same gauge in the same location on my 370z for roughly 3 years now. Photo attached. That was a custom fitting that we welded and machined on to just "get it done" on the spot those years ago. It has held up for me in daily driving conditions and pretty bad heat/humidity that we get up here.

So while I cannot promise that the gauge will last forever, I can confidently say that chances are great it will last a very long time... and that if it does ever fail, they are very inexpensive to replace (typically about $20-24 retail).