Registration validity for casual and non-resident taxpayers requires pre-registration tax deposit and allows officer to grant limited extensions. Certificates for casual and non-resident taxable persons are valid for the period in the application or a limited statutory period and supplies may be made only after issuance. Applicants must deposit in advance tax equal to the estimated liability for the registration period, and where an extension is sought must deposit an additional amount for the extension. Deposits are credited to the electronic cash ledger and utilised per the rules governing that ledger.