We're told we're supposed to have an income source in retirement outside of Social Security, since those benefits alone aren't enough to live on. For most of us, that means establishing a nest egg in the form of an IRA, 401(k), or both. But a large number of small-business owners have a different sort of backup plan for covering the bills in retirement: their businesses.An estimated 42% of small-business owners say that their businesses will serve as their personal pensions, so to speak, according to data from New York Life.