Registration validity for casual and non-resident taxpayers requires fixed certificate duration, possible extension, and advance tax deposit. The certificate of registration for a casual taxable person 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 by the proper officer for a further period not exceeding ninety days on sufficient cause. Applicants must make an advance deposit of tax equal to estimated liability for the registration period (and for any extension) and such deposits are credited to the electronic cash ledger to be utilised as provided under section 49.