Registration validity for casual and non resident taxable persons requires advance tax deposit and limited term certificates. Registration for casual and non-resident taxable persons is time limited and conditional: the certificate of registration is valid for the period applied for or ninety days from its effective date, extendable by the proper officer for a further limited period on sufficient cause. Applicants must make an advance deposit of tax equal to estimated liability for the registration period, and any extension requires an additional deposit; deposited amounts are credited to the electronic cash ledger and utilised as provided.