If you are using a .com.au, .net.au, .org.au or any other .au domain:
When your domain first expires it enters into what is called serverUpdateProhibited or serverHold status for 30 days. During this time are you are able to renew your domain without incurring a penalty fee.
After the initial 30 days the domain status will change from Expired to Pending Delete. This lasts for about 24 to 48 hours.
After this final stage, the domain name is then deleted from the .au registrar and is up for registration by any eligible party.
If your are using another extension such as .com, .net, .org, .info, .biz:
When your domain first expires it enters what is called Domain Name Grace Period (DNGP), this lasts approximately 40 days. You are able to renew your domain during this time as long as you are willing to pay the renewal fees.
Following the GNGP, your domain will enter a 30 day ‘Domain Name Redemption Period’ (DNRP) where the domain is still able to be purchased by the original registrar however reclaiming the domain can be a time consuming and costly process (can take up to several days).
Following the DNRP the domain will enter a 5-day Pending Delete Phase. This is the final phase until the domain is finally released and made available for registration by any eligible party.
Domains that are freshly released are marked as a Dropped Domains these domains can often be sought after by parties who are looking to purchase domains to re-sell back to the original registrant or other interested parties at a profit.
There are a few obstacles in the way of you reclaiming your domain but don’t feel too dissuaded, dependant on how important it is for you to have that domain name, You can either pay the penalty+renewal fees or if you are willing to wait until the redemption period is over, make sure to be ready to reclaim your domain as soon as it is available for registration!
Note: To prevent this from happening in the future, remember to set Auto Renewal on your domain so you are automatically invoiced at the time of the renewal, you are able to disable this setting if you change your mind.