I want to say right away that I don't know much about cars but I do tend to run over nails. If there is a nail on a huge road and a lot of cars are driving on it, then luckily for me my car will be the only one that will pass it. I also can't usually tell when a tire is flat until a family member reminds me it's flat. So, with that disclaimer I have to say I had to go through the manual to figure out how to set this up because I don't know how to read psi or what a normal psi is for that matter so I'll just leave it at that doing, average recommendation. what the machine reads. I really like the different options for running this device, but my favorite is solar power. We live in a fairly sunny state, so it's nice to know the device is always charged and ready to go. I also noticed that there are 2 sets front left and front right and 1 set rear left and rear right. My family has a minivan (4 wheels) and a sedan (also 4 wheels) so I don't know why 6 are provided. So I had 4 on my minivan and 2 on my sedan. The fact is that the device can read numbers only at a certain distance. Since I have 2 on the sedan I can't tell if my tires are flat until I literally park right at home next to the minivan and then start the sedan while I check the numbers. It's not as bad as it sounds, plus I'm forgetful so I'd forget about it if I took it to every car.