Record-keeping obligations require professionals to maintain specified books and retain records, with a threshold exemption and retention rule. Persons in specified professions must maintain enumerated books and documents, including cash book, journal (if applicable), ledger, carbon copies or counterfoils of serially numbered bills and receipts, and original bills or payment vouchers for expenditures, subject to small-sum exceptions and a threshold exemption for low gross receipts. Medical professionals must additionally keep a daily case register and an inventory of consumables. Records are to be kept at the principal place of profession (or separately where maintained) and retained for six years from the end of the relevant assessment year, with continued retention where an assessment has been reopened.