If you are a service provide (within the taxable services bracket) and your income exceeds Rs 9 lakhs in a financial year, it is mandatory for you to get service tax registration so that the government can identify as you as the assessee. You can pay your Service Tax without registration too but it may invoke a penalty of up to Rs 1,000 under Section 77 of the Finance Act.
According to rule 4(1) of Service Tax Rules, the person is liable to get the service tax registration done and pay the tax within 30 Days from the date on which it is levied.
Besides the statutory requirement, some of the other benefits of Service Tax Registration are:
Government departments or offices look for registered service providers only. So, if you are vying for a government project (such as housekeeping services), ST registration may come in handy.
Registering for Service Tax does not mean that you have to pay tax until your income crosses the threshold of Rs 10 lakh in a year. However, once you have paid the tax, you have to file ST return regularly.