No matter what type of HVAC system your home or commercial building employs, it's important that you remember the system is made up of electronics and mechanical parts. Much like a car, the components of your HVAC system will eventually wear down or even fail entirely.
That means you need a plan in place for keeping ahead of these inevitable, but predictable problems. The simplest way you can stay ahead of them is with an annual or quarterly HVAC maintenance plan. Not sure what should go into that plan?