How long should books of account and documents be kept and maintained?
Books of account and documents should be kept and maintained for a period of 6 years from the end of the relevant assessment year.

 However, if the assessment in relation to any assessment year has been reopened under Section 147​ within the prescribed period, all the books of account and other documents which were kept and maintained at the time of reopening of the assessment should be kept and maintained until the assessment so reopened has been completed.​