What happens to a domain once it expires or is cancelled?
Once the Domain name has expired or been cancelled you will not be able to use it and any email accounts will stop working.
For NZ Domain names they are put on hold for 90 days, during this time you can renew the domain. Once this period has ended the domain is released and available for purchase.
Global Domain names are slightly different, After cancellation of a GLOBAL Domain (.com, .net, .org, .biz) its status is changed to "Client Transfer Prohibited" and the domain stays in this status for 30 days. If the domain is not renewed in this period, the status of the domain changes to "Redemption Period" for the next 30 days. The renewal in this period is at a cost of $150 USD + $30 NZD + Any renewal charge. The domain will become available to be re-registered after the next 5 days of this redemption period.