They're invaluable if you are going to wheel much. We can air down 2 sets of tires while someone else does it manually for one set.
Another one to consider is Oasis. I like my Stauns and have no regrets and they have been around forever. They are probably the most accurate.
I check mine periodically on my spare tire by putting each on, letting it air down and then checking to make sure it got down to 18 psi, which is what I have them set for. I then air the spare back up and check the next one.
It's a no brainer to walk around your truck and screw these on each tire and then chit chat with someone else as they squat, push in the valve core, check the pressure..... repeat ...... for each tire.
