Retention period for GST accounts requires records kept long after annual return date, extended during appeals or investigations. Every registered person must retain books of account and other records until the expiry of seventy-two months from the due date for furnishing the annual return for the year to which those records relate. If the person is party to appeal, revision, other proceedings or under investigation for an offence under Chapter XIX, records relevant to that subject matter must be retained for one year after final disposal or for the general retention period above, whichever is later.