Any nay sayers on donuts can be who you call upon to come out and find your sprinkler heads in about 2 months this summer. ST Augustine smothers them. Donuts get covered in time if you don't trim them but at least you increase the size of the head for location. Your lawn service will most likely NOT trim them. Mine get trimed every week. Why? I do them.

Your neighbors card playing group or whatever social events will drive on them if you live in a Villa. Will they give a crap about your sprinkler head while they park on it? Nope. A broken donut saved your head.

FL is a whole different animal.

Forget about what you did up north - in every way.

Get them at Ace Hardward as well. Keeps someone from breaking your sprinkler heads, but still need to be cleaned out or raised periodically as they sink or the grass grows over them. An ounce of prevention is more than a pound of cure.

If someone parks on the street and drives over them like we have had happen a few times you will understand why these are good.

I could not agree more.

Never had them in 13 years, I see grass grow inside my neighbor that has them, he has to cut out the grass.

They make it easy to use Roundup 3-4 times a year to keep that from happening. Use a paintbrush rather than a sprayer to avoid overspray.

Besides keeping the St. Augustine grass at bay, another benefit to the donuts is it makes it easy to find all of your sprinkler heads. Should you have an issue, such as a broken pipe, it is a cinch to walk around and see which head or heads are not popping up.

You said YOU were riding around on a John Deere up North, you could see if any sprinkler heads stayed up slightly and not cut them off with your mower.
Things are different here. The landscape companies cutting your lawn will slice off any raised heads quicker than lightning. IF you cut your own lawn, then no problem.

I use a donut cutter from online Sprinkler Warehouse around the donuts once a year to keep them from disappearing in the grass.

While your yard is new be sure and draw a diagram of where your sprinkler heads are.
The St. Augustine grass will bury them every year.
It’s easier to find a donut than a sprinkler head.

Not needed unless the yard crew rides over them and breaking them or the grass growing over preventing the heads from popping up to water the yard correctly. That then would cost money to replace or repair the heads more frequently.
St Augustine grass is like many have not had the opportunity to deal with in different areas outside of Florida. Just call them piece of mind.

If you do not have a curb to protect and separate your yard from the road it's only a matter of time before someone drives over your sprinklers and breaks them. We had a next door neighbor who routinely drove over ours. The rings saved us from costly damage. Unfortunately the sprinkler heads were placed right next to their driveway and right along the edge of our yard along the street. Terrible planning,

Maybe unnecessary if you personally mow the lawn. However, cautious and observant don't describe most lawncare guys around here.

A timely topic indeed. I spent a few hours yesterday afternoon cutting out donut holes and unearthing several which got buried by the St. Augustine.
What a PITA..

Service and Maintenance is a key factor in putting in donuts. The sprinklers have small filters on them that need cleaned periodically for them to work properly and the donuts make it way easier to clean them and fix problems. The water that goes thru sprinklers is very dirty reclaimed water down here.