Registered trademarks have a 10-year validity and can be renewed indefinitely. The Registrar has set a wide window for you to do so, beginning from 6 months before the date of expiry. Even if you've forgotten, as even large organisations tend to do, you will be sent a notice to the registered address regarding the expiry before the 6 months is up. If you still do not file for renewal, the Registrar may advertise its intention to remove the trademark in the Trade Marks Journal. This is, however, likely to happen only 12 months after the expiry date. Between 6 and 12 months after expiry, trademark registration can be renewed on payment of a fine through a process called restoration.