A slight whining or high-pitched noise coming from the sprinkler valve is a sign of a small leak or slow leak. While this sound is sometimes accompanied by a telltale trickle of water, the leak may appear not in the exterior of the valve but in the valve shutoff. The sound comes from water channeled through a small hole, the way air is channeled through the stops of a whistle. A leak in the sprinkler valve, whether inside the mechanism or on its exterior, means the valve will require replacement. If a sound is present but no water is streaming out of the valve, try tightening the connectors joining the valve with the pipes before servicing. - This is what I read from a Google search. I ended up replacing it after trying the water pressure suggestion above.

It's entirely dependent on your climate, soil characteristics, and the existing moisture content of your soil. I suggest you get a $10 moisture meter from Home Depot and figure it out that way.

I have a succulent "island" in the middle of my lawn. My talented lawn guy diverted the sprinklers around so they don't hit the island. I hand water the island about every 2 weeks. I'm converting my yard slowly #1 because my backyard is all brick and gravel and my twin grandbabies will need a place to run, and #2 we are in a chi chi neighborhood (we're at the unfashionable end) that sports lawn and boxwood. Don't want to freak out the neighbors! Of course we have received numerous compliments on the yard thus far.

gardening is an art.. not a science ... and when you make it into a science.. imo.. its just no fun anymore .. i dont understand.. with the vagaries of mother nature.. and her weather.. how you could expect anyone to come up with a system of what you should do in your yard.. in your soil.. with your ambient weather ... and surely minimal winter temperature.. zone.. has nothing to do with winter watering .. so why are you fixated on that ... temperature is one of lest important WINTER issues.. dont you think?? also.. if you were somewhere where you actually had a winter.. i would tell you that dormant plants dont need much water at all.. but i surely dont know z9 nor CA... but you need to take that into consideration ... do your plants even go dormant for winter??? .. teach me something ... ken