When your domain expires you have a limited hold period in which to renew the domain name before it becomes available for someone else purchase. The length of this holding period varies depending on the type of domain.
.com.au domains have a 30 day hold period
.com domains have a 45 day hold period
.co.nz domains have a 90 day hold period
If you renew your domain name during this hold period, the renewal will backdate to the original domain expiry date. So we recommend renewing your domain before it expires.