What happens when my Premium subscription expires?
You can see on "My page" when your subscription expires. Two weeks before your subscription lapses you'll get a message.
When you choose not to renew, your private queues and forums will no longer be available to you. They are kept for some time, unless you request otherwise, so that everything is where you left it if you choose to return.
If you downgrade from premium gold to premium, your queues go from 24 member to 8 members, and the gold-only features will not be available anymore.