When you decide to realize a home automation system, it is not necessary to implement immediately all functions. You can start with a set of basic functions and then complete your system step by step, according to your needs and budget. This is made easy by the native modularity of the home automation technology. The condition for this is to accurately plan in the design phase a full predisposition of the system. It means a very low additional cost, but offers remarkable advantages in the future. In fact, it allows the later expansion and completion of the system with minimal impact.