When you register a domain name, be sure to update the Whois information to contain your email. Later, when it is time to renew, you will get an email reminder.
If you do not want to rely on email, you can perform a Whois search for your domain, and check the expiration date.
IMPORTANT: Host NIT domains can be managed and renewed via our domain control panel. Please read the related article.
Other registrars: Before your domain expiration date, you must contact the company where you bought the domain name (the registrar). Tell them which domain name you want to renew, and they will help.