We have 6 of this type of Rain Bird Lawn Sprinklers in our back yard. They are an excellent product but that doesn't relieve the need for a certain amount of maintenance. They were installed at the time our house was built back in 1968. We are the second owners having bought the house back in '81. This sprinkler head sets in a plastic bowl with a 6 inch diameter lid. The lid and sprinkler pops up a couple inches when the water is turned on which lets the system operate. The sprinkler and lid drops down when the water is turned off and is flush with the ground so it doesn't interfer with mowing. It can be adjusted to cover whatever part of a circle desired and the sprinkler stream can be controlled to shooting out as much as 35' or as little as 10 feet. Farmers use to think that frost action brought rocks to the surface instead of acknowledging the impact of soil erosion. Likewise, we don't realize how the level of our lawns build up over a period of years. Two of ours were not working properly so I took the lids off and cleaned out the dirt and muck that had accumulated in the container. They were both in a location with little grass so it was more of a case of sediment collection than "soil build-up". A couple of the others do show the build-up of the soil level. After cleaning, I wanted to make some adjustments; so while I was in the backyard watching the effects of my adjustments, Elaine was in the garage at the control box turning the water on and off. If we would have each had a phone, it would have simplified the project. It doesn't take much to keep old people busy.