It depends on the airflow situation in your home.
There are three main scenarios that are solved with Flair Smart Vents: rooms with too much airflow, rooms with too little airflow, and uneven temperatures across the home.
Too Much Airflow
This room gets too cold in the summer and too hot in the summer. Start off with a Puck and Smart Vent for this room. This will help redirect airflow away from this room to keep it temperate across seasons.
Too Little Airflow
This room gets too hot in the summer and too cold in the winter. Get a Puck for this room and get Pucks and Smart Vents for other rooms to redirect airflow toward this room.
Maybe you have a room that gets too hot when the sun hits it regardless of the season. Or a room that stays cold during summer and winter. Or you might have a home with a combination of airflow issues. For these homes, we recommend replacing all vents with Smart Vents. Keep in mind that you don't need to replace vents in small bathrooms or closets.
Total Smart Home Control
For the smart home enthusiast, using Smart Vents in combination with an ecobee or Honeywell smart thermostat can bring the ultimate in temperature control to your home.