There are several organizations that require your Social Security number, including your employer, the IRS, and financial institutions. But there are many other organizations that might ask for your Social Security number but don't really need it, including hospitals, doctors, insurers, utilities, schools, and retail stores.
"Many forms, like those in doctors' and dentists' offices, have a space for your Social Security number, but it may not actually be needed if your insurance company provides its own identification number for your coverage, as most do," says Neal Stern, a certified public accountant and member of the AICPA's National CPA Financial Literacy Commission. "Provide your Social Security number only when it's really needed, and don't be afraid to ask." If someone requests your Social Security number, offer alternative forms of identification or ask why they want it and how it will be handled.