Hi, WiFi signal degrades with distance from the AP, -65dbm has become the industry standard as the recommended limit of signal strength/coverage to ensure that the connection from the device to the AP is still stable, once the signal drops below -65dbm the connection starts becoming unstable, i.e. packet drops, intermittent loss of connection, etc. You will still be able to get a connection at -72dbm but you would see increased latency and potentially packet loss dependent of how much the signal strength fluctuates