What is mandatory to maintain books of account in the case of non-specified professionals?
Non-specified professionals are required to maintain books of account if the income from their profession or gross receipts of such profession exceeds the threshold given below:

 For individual or HUF: if the income from such profession exceeds Rs. 2,50,000 or Gross receipts exceeds Rs. 25 lakhs, in any of the 3 years immediately preceding the previous year.

 For others: if the income from such profession exceeds Rs. 1,20,000 or Gross receipts exceed Rs. 10 lakhs, in any of the 3 years immediately preceding the previous year.​