This depends on the quality of the heads and the system that you install. Cheap heads may only last about 2 to 3 years, while better quality ones can last 10-15 years. The average life of the sprinkler system is about 20 years. If you take proper care of your system, it should be able to last the maximum number of years. The best time to do maintenance work is between seasons. They need to be checked between winter and summer to ensure that colder temperatures did not ruin the pipes and the heads. This is called winterization. This operation is usually done by a professional. Also, ask them for maintenance tips and how you can prolong the life of your system.