As I understand for a client server model, it's common practise to send input to the server and then the server applies the input to update the state of the game. The server then sends updates to clients regularly. The client in the meantime does prediction, before it receives the "true" state.
My question is how often to send input. Surely it should be sent every frame otherwise some input (during frames which are not sent) will not be processed by the server. Will this be too heavy for the network. What is common practise?