In Opal, we provide short-lived access to resources. This can be scoped to a time period or event. After this time period has expired, you cannot start sessions or use the resource. You can see how much time you have left to use this resource in the top right.
For session-based resources, you are able to start sessions that last for 12 hours and your credentials will auto-expire every 15 minutes. You can start new sessions as long as your access to the resource has not expired.