In larger Poway homes around Green Valley and Old Coach, there are more faucets, more showers and more valves, and hard water wears on all of them. It shows up a little at a time, with a bathroom faucet that won't quite stop dripping, a kitchen handle that has to be jiggled, or a shower in a back bathroom that keeps dripping long after it's off, which can go unnoticed when that bathroom doesn't get much use.
Most of it is a parts job. Drips usually come from a worn cartridge or seal. Stiff handles usually mean scale inside the cartridge. A shower valve that won't shut off all the way has a worn cartridge or worn seat behind the wall, and that one is worth catching early. The contractor can replace the worn part or tell you plainly when the fixture has reached the end.
The service covers faucets in the kitchen and bathrooms, tub and shower valves, plus the shutoffs under each sink. Repairs when they make sense, and replacements when they don't. You get the options in plain English and make the call.