Registration validity for casual and non-resident taxable persons requires limited-term certificate and advance tax deposit credited to electronic cash ledger. Special provisions require that registration certificates for casual and non-resident taxable persons be valid only for the period specified in the application or a limited statutory term, and supplies may commence only after registration. Applicants must make an advance tax deposit equal to estimated liability for the registration period, and an additional deposit if an extension is obtained. Deposits are credited to the applicant's electronic cash ledger and utilised according to the prescribed ledger utilisation rules.