Who should file it?

Form 121 is most useful if:

• Your total annual income is below ₹2.5 lakh (basic exemption limit)
• You fall under a lower tax slab and don't want TDS deducted upfront
• You prefer to manage your tax liability at filing time rather than through automatic deductions

Even if your income is above the exemption limit, filing Form 121 prevents unnecessary upfront deduction and improves your cash flow through the year.