In order to be an informed consumer you need to understand the different components of a system. The best systems professional will help you determine what components you need to serve your home or business.
Your systems professional should discuss what options fit your home and/or business and lifestyle, for instance, do you have small children, pets, are you away from your home for long periods of time, do you have expensive items such as jewelry you want to protect. All of these things may factor in to determine which system is best for you.
You may decide to install a system for a specific purpose but keep in mind in you can link other devices into your system such as security, fire, entertainment, controlled heating and lighting, and carbon monoxide detection. There can also be cost savings to combine these features versus installing them at a later date. It all depends on what you want and what suits you best.
The best systems professional will customize your system for your needs!