A common question, with a not so clear cut answer, is what happens if my domain name expired? The short answer is, hope it has been 30 days or less.
When a domain is set to expire and the owner doesn’t renew it, it will go into a 30 day holding period during which the owner has the chance to renew it with no penalty. After 30 days it goes into a redemption period during which the owner can renew it for an addition fee (usually somewhere between $100-200 depend on registrar). Following those 60 days it then goes into cancellation mode and will eventually be back up for sale to the public somewhere between day 75-90 (again depending on registrar).
If you have reached the 60+ day mark and still want your domain, you have several options. You can use a drop list registrar, you can place a back order, or you can take your chances and hope nobody else wants it.
A drop list registrar is one who uses extra resources to try and grab valuable domains (or domains people have requested) at the moment they are dropped from the ICANN database for the public to buy.
A back order is a cheaper option (usually around $20) but doesn’t guarantee you are the only one wanting the domain. It simply gives you the first shot at getting it (along with anyone else who paid the fee).
Waiting and hoping that nobody else wants it and hasn’t put in a drop list request or back order is obviously risky if you have a good domain that you really want to keep, but most likely if that is the case you would have renewed it in the first place.