Record retention requirement prescribes multi year preservation of GST books; appeals or investigations extend retention after final disposal. Every registered person required to keep books or records under section 35(1) must retain them for seventy two months from the due date of filing the annual return; if the person is party to appeal/revision/proceedings or under investigation for an offence under Chapter XIX, records pertaining to the subject matter must be retained for one year after final disposal or for the general retention period, whichever is later.