Filing a tax return voluntarily is worth it only if a tax refund can be expected or a balance carried forward loss becomes apparent.
A tax refund is only possible if taxes have already been deducted from salaries or advance tax payments have been made.
If the calculation results in a negative amount, i.e., no refund, you can decide for yourself whether you want to file a tax return or not. If you fall under the tax return mandate, you do not have a choice in the matter.
A balance carried forward loss is possible when your expenditures and professional expenses in a year outweigh your income. The loss can then be carried over into the following year or years and be subtracted from your future earnings. This option is especially relevant for students who normally face high expenses during their university education.
If filing a tax return is mandatory for you, you have to submit it by May 31 of the following year, regardless of whether a refund or additional payments are due.