One time of spray can last for at least 6 months.
We recommend once every 6 months with maintenance spraying on the ports with wear and tear (e.g. microphone and charger port). Applying two layers DOES NOT make it more waterproofed.
The spray provides IPX4 and IPX7 water protection and you can apply IPX7 extensive protecting to your device.
Feel free to visit X2O Product Page for more information.