If you don’t agree that a fire alarm system is more than a fire alarm system, you should probably revisit Chapter 21, Emergency Control Function Interfaces, in NFPA 72 2016, National Fire Alarm and Signaling Code.
A good fire alarm system design becomes a function of how well you understand fire-protection principles as well as the requirements of NFPA 72, National Fire Alarm and Signaling Code, and NFPA 70, National Electrical Code (NEC).
The calls vary, but all have a similar theme: “My fire alarm system needs work. Can you help?” Of course, the answer is always yes. But professional contractors know they must make a thorough investigation of the installed system before determining the scope of the work.