Security Dealer & Integrator Magazine, February 2009 edition, has an interesting Q&A with the AHJ [page 26]. Fire Marshal Cutrer makes some suggestions, including adding smoke and carbon monoxide detectors to residential systems [presumably burglar alarm systems]. He also suggests servicing those components. What caught my eye was the heading of the article, "Boost Your Business With Inspection and Maintenance". My first thought was that the article might have been titled, "How to put your company at risk and go out of business fast". Here's why.
Of course it can be advantageous for home owners to add smoke and co detectors, and to have those components inspected and serviced periodically. However, you need to be careful that you have not given the home owner unrealistic expectations regarding the systems. A smoke detector is not a fire alarm system. A co detection device is no guarantee that injury or death will not occur in that premises.
Your contract must describe your systems and their limitations, especially when you are installing life safety systems such as fire and co. Your contract must also carefully describe what services you will actually be performing. Almost without exception there should be no "maintenance" obligation or expectation in your contract; you're not going to do it. You can offer an inspection contract - if you're going to do the inspections, and you can offer a service contract which will require the subscriber to call you for service. Get and use proper contracts - www.alarmcontracts.com.
Unless you are going to install a fire alarm system in accordance with AHJ requirements or at the very least NFPA standards, be certain your contract and promotional material [and your estimates if you use one] do not describe the system as a fire alarm system. If you are installing a burglar alarm system and including a few smoke detectors, then that's how you describe it, and there should be a disclaimer that the fire components are not a fire alarm system.