The smart home is designed so that it can be customised to suit the needs of the people living in it.
A good starting point is to install systems for:
If there are devices that you think you would not use, these need not be installed.
If you have any specific needs, additional equipment can usually be installed. If the system is capable of comprehensive coverage, such as LonWorks® or BACnet® based system, then adding compentents and systems as needed becomes a viable approach.