Registration period and mandatory advance deposit govern casual and non-resident taxable persons' ability to make supplies. A certificate of registration for a casual or non-resident taxable person is valid for the period specified in the application or ninety days from the effective date, whichever is earlier, and may be extended on sufficient cause. The applicant must make an advance deposit equivalent to estimated tax liability for the registration period, and any extension requires an additional deposit. Deposits are credited to the electronic cash ledger and utilised under the prescribed utilisation regime.