With times evolving, a large part of today’s taxpayers works for itself rather than taking the conventional 9-to-5 job. It is common to see people quitting their comfortable jobs and becoming freelance professionals, consultants, doctors, interior decorators, etc.
India's tax laws have made it mandatory for individuals in professions like legal, medical, engineering, architectural, accountancy services, etc, to maintain books of accounts so that tax authorities can compute their total income. A freelancer who is into any of these professions would also be bound by this mandate. A freelancer might be relieved of this if she opts to go for presumptive taxation.