A household water pressure regulator reduces the water pressure from the public water main to a pressure that is usable by the customer and compatible with normal household plumbing and fixtures. It also helps prevent pressure surges from entering the household plumbing from the public main.
Pressure regulators are typically set from the manufacturer and the suggested range is 25-75 psi. If the water pressure reading of your plumbing is higher than 75 psi do not ignore it, this condition may be indication that the pressure regulator is worn and failing or has already completely failed. Recommended water pressure in a home is 55 psi,
The California Plumbing Code lists the maximum safe allowable pressure at 80 psi in any building. Most faucet, toilet and water heater manufacturers void their warranties when water pressure exceeds 80 PSI, and if you have a home warranty, some warranty companies void your coverage if your home has excessive pressure.
The life expectancy of a water pressure regulator is most commonly in the range of 10 to 15 years. However, you may see a regulator malfunction at 3 years and you will see a regulator still working at 20 years old. Most manufacturers recommend swapping the pressure regulator valve every 5 years and most plumbing contractors would suggest you change the valve every 10 years. The operation of a pressure regulator is basically the action of a spring and rubber gasket. After open and closing thousands of times, it will eventually wear out like any other moving part.
I recommend testing your water pressure once a year by attaching a pressure gauge to the hose bib at your exterior walls. Always test the pressure after the pressure regulator, testing at a hose bib at rear exterior walls is typically the best place.