The law only requires you to get a Federal ID Number, or EIN, if you are going to have employees or set up an entity like a LLC or corporation. With that said, Cruise & Associates recommends that every full time business obtains one, regardless, if you have employees or not. The EIN number is basically equivalent to a social security number for your business. If you don’t get an EIN, you will have to use your personal social security number, which could possibly lead to other problems.