They do go bad, but not often. The diaphragm develops a leak. Rog, I would carry 2 spare filters just to be sure. I went thru 2 in less than 20 miles from a bad batch of fuel. A tanker was delivering a load as I filled up, and there must have been a bunch of crap in the bottom that he stirred up. I got about 10 miles before mine died, luckily I had just changed the filter and had picked up a couple more at the parts house a day or two earlier. Having a filter delivered in the middle of nowhere would not be cheap, so I always have 2 in the truck now. Also, be careful with that tiny vent screw. It is NOT available from GM unless you buy the filter head, which is a couple hundred $. You can shop around for the best price for the filters--they are all made by Racor regardless of the name on them. Just make sure you get the latest version, #3.