It is very easy to replace the sprinkler heads which I just did in a matter of a few minutes. There is one issue and I want to point that out first. The unit is covered with a glued on paper tag that explains all about he sprinkler head. It absolutely will not remove easily. It took me 15 minutes to get the paper label off the two heads that i purchased. I eventually had to heat the label with a hair dryer and even then they would not remove easily. This is just a nagging point with me as no label should be that hard to remove. You may be asking why did I want to remove the labels. Well in my case the two spray head were about 12 inches above ground in my flower beds and I really did not care for all the advertising of Rainbird in my front yard. In my case all I had to do was unscrew the heads fro the 12 inch extender pipe and then screw the new heads back on. Be sure and check the radius area on the old sprinkler head so you can get the exact duplicate. This is a very easy job. Be care not to unscrew the riser pipe other wide you stand the chance of getting some soil or sand in your water line. In the event you dod not have a rise pole and the sprinkler head is screwed directly into your sprinkler water line, it is still an easy job. Just remover the dirt or sand around the area where the headed is connected to the pipe and one again be careful not to let dirt or sand get into your water line, then just screw the new replacement head back into the water supply line. You have just saved yourself a$50 to $100 service call. I you want to do a professional job, put a small amount of teflon tape around the threads before you screw the head into the pipe. Now you are a professional sprinkler head replacement persons.