Starting to have low water pressure on the water inside the house and the outside bibs?

Why is there a pressure regulator behind a pressure switch controlled pump? Pump pressure switches function for years and may finally burn the points or break springs but they don't change cut in/cut out settings by themselves. If you know what the previous settings were and that's what the guage registers you very likely don't have a defective guage. Before you start cranking on adjusting screws you need to suspect a broken plug in that pressure reducing valve, or by any chance is there an in-line filter system or water softener? A suggestion: A thirty five or forty pound kick out pressure wiIl give you all the household pressure you need and will increase the life of your pump, plumbing, faucet seals and of course, the pressure reducing valve. Incidentally, hose bibs don't have screens and tank bladders have a specific precharge and you do not change that when you change pressure switch settings.