If you register a domain, you usually pay an annual fee to your registrar. That means that if you want to keep your domain, you have to renew it on a regular basis. Thus, you are the owner of the domain until you pay the fee for it. and at the same time you cannot be obliged to keep paying for a domain name you do not want anymore.
Domain extensions differ in price, and also, different registrars are offering the domain extensions at different prices. The annual fee of a .com extension is usually around 9 USD, whereas .luxury extension costs as much as 550 USD currently.
At most of the registrars you also have a possibility to renew your domain for more than a year, e.g. GoDaddy offers the possibility of domain renewal for a decade. Most registrars offer the option of auto renewal and take the annual fee automatically from your credit card if you authorize them. The registrars are obliged to send you two emails to notify you about the expiration: one 1 month and one 1 week before the domain’s expiration date.
If your domain expires and you failed to renew it, you still have a chance to get it back: according to ICANN regulations, there is a 40 day grace period. In this period every service stops working, however, if you renew your domain within this period, all services will be automatically reset.
After the grace period the domain enters a 30 day redemption period. During this period it is still only the original owner who has the right to renew the domain – however, for an additional fee in this case. The fee is around 70-250 USD currently, which does not contain the renewal price.
After the redemption period the domain will be in pending delete status for 5 days. In this period, other interested parties can apply for securing the domain for themselves. If no one is interested, the domain will be deleted and is then available for new registration.