Registration validity for casual and non-resident taxable persons requires certificate before supplies and limited-term validity with possible extension. The certificate of registration for casual and non resident taxable persons is valid for the period in the application or a limited ninety day term, issuance being prerequisite to making taxable supplies; a one time extension for a similar additional period may be granted on sufficient cause. Applicants must make an advance tax deposit equal to their estimated liability for the sought registration period, and where an extension is sought must deposit an additional estimated amount; deposits are credited to the electronic cash ledger and utilised under ledger rules.