Only 1 WiFi Hub is needed if you want to connect all your SmartThings devices. But if you want to use the Hub as a WiFi mesh to extend your WiFi signal coverage, you will need at least 2 units for the mesh capability to work.
Here are the recommendations on the number of units based on the size of the home:
- 2 Bedrooms - 2 units
- 3 Bedrooms - 3 units
- Multi-storey homes - 3 or more units