We oftentimes do see flashing incorrectly installed thus then causing problematic stucco due to water intrusion. This is best remedied by a licensed roofer, and we do have some that we could recommend. We then come in and provide the stucco repair upon completion of their work.
We recommend a NP1 rated caulk or higher. All windows, doors, adjoining and adjacent materials need caulking as well as any penetrations into the wall, i.e. light fixtures, alarm systems, etc. Caulk does need to be replaced periodically and is part of the maintenance process of keeping your stucco in good shape.
All sprinkler heads should be checked to determine that the spray pattern is away from the wall. Over the course of time, spray heads and rotor head may vibrate out of alignment thus causing the spray pattern to change. All sprinkler heads should be placed at least 18″ from the wall.