I use my EIN every time I'm able because I don't like giving my SSN to a company I can't physically "see." Who knows what their security is over their data files? I've been the victim of identity theft once before and it was a nightmare so I only give my SSN if I absolutely have to.
Some people here have said their local bureaucracy will tax them if they have an EIN -- but all that means is their business should be taxed and they're trying to avoid it. I have a business license that allows me to operate out of my home; I pay $50 a year for it. Other places I've lived it was $250. Some tax a percentage of your sales. Some towns in California are particularly insidious about demanding people get a business license for every community in which they do business. I have a friend with a business in Hawthorne and the city of Hawthorne came in and harvested his vendor list and sent letters to every one of them demanding they either get a Hawthorne business license or prove they never set foot in that town to "sell" anything to him. Yes, they wanted every traveling salesman who passed across the town border to pay a tax to Hawthorne on the resulting sale.
I would suggest you talk to someone about your local ordinances and find out if you need a business license to operate a business out of your home when you technically do most of the work elsewhere. If you find you don't need a license, then get the EIN. If that would cause you an expensive problem, then give out your SSN.
The difficulty here is "you can't have it both ways." If we are presenting ourselves as a business, not a hobby, for income tax purposes so we can write off all our expenses against our shopping income and deduct any resulting loss from our other income, then we can't/shouldn't simultaneously pretend we are a hobby to our local government and not really running a "business" out of the home.
The more computerized everyone gets, the easier it is for your state, who knows you filed a Schedule C on your tax return, to report that information to your town, who will see that you either do or don't have a business license. And that can happen whether you have an EIN or not.
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I pray it does not occur that the last thing I did before I died was vacuum the house or eat broccoli.