SSA, to which you refer in your question, is the acronym for the United States Social Security Administration. I assume that you are instead referring to the differences between Social Security Disability Insurance (SSDI) and Supplemental Security Income (SSI) which are most commonly confused.Social Security RetirementSocial Security Retirement benefits are entitlements (the right to guaranteed benefits under a government program, as Social Security or unemployment compensation) and require the following:meet the required work credits,paid into Social Security and Medicare through payroll deductions or self-employment,are of retirement age, 62-70.Simply put, SSDI is available to workers who have accumulated a sufficient number of work credits and become disabled and unable to work before retirement age. SSI benefits may be available for disabled, low-income individuals who have never worked or have not earned enough work credits.Many people mistakenly believe that SSI and SSDI are the same things. Where in fact, they are two entirely different programs. Despite the fact that both programs are managed by the Social Security Administration, and medical eligibility for disability is determined using the same requisites for both programs, there remain distinct differences between the two, the main point in error is funding.Social Security payments are funded by the Social Security trust fund.SSI is financed by U.S. Treasury general funds.Social Security is an earned benefit (entitlement) which workers pay into through earnings deductions or paid from self-employment.Social Security Disability InsuranceSSDI is available before retirement age if the individual becomes disabled, (SSA definition: workers who meet medical and insured requirements) and has accumulated enough work credits. Generally, you need 40 credits, 20 of which were earned in the last 10 years ending with the year you become disabled. There are provisions in place for younger workers who may qualify with fewer credits. Unless you are blind, you must have earned at least 20 of the credits in the 10 years immediately before you became disabled.Supplemental Security IncomeSSI is a government program administered by the SSA that provides stipends to low-income people who are age 65 or older or disabled. SSI is based on financial need for individuals or couples that have not accumulated enough qualifying hours and become disabled. If the household countable income exceeds the current income limits, the determination will indicate that there is no need. For 2017, the income limits are $8,830.84 for an individual or $13,244.80 for a couple. SSI also outlines guidelines for couples: if you are both disabled (SSA definition) and demonstrate financial need (insufficient or no income and less than $2,000 in assets), you may qualify for SSI.