The early systems were pretty basic but the later versions are both accurate and tell you specifically what each tire has for pressure. You can monitor manually and visually as well and you should just to verify you have correct pressures. Running a tire under inflated is the fastest way to ruin one. I've not had an issue with any of the vehicles equipped with it in the last 10-15 years. Most tire shops can reprogram if they rotate tires. If they need to but I think most vehicles have the ability to relearn the positions without any external programming required these days.