Some clients respond faster to an application for a gig than others. The response time varies from one client to another. When you open a gig, you can see the average response time for that client. This gives you an indication of when a client will respond. Once the client has responded, you will receive a push notification whether you have been accepted or rejected. If it takes a little longer before you hear anything, you can always contact the client.
Note: in principle, a client can accept you one minute before the deadline, which means that you are expected to be present. So be sure to cancel yourself within the cancellation deadline if you have made other plans.