My special place to write and think about social security disability
A credit is earned roughly every quarter of the year a person works and earns at least a minimum amount of income (established each year by Social Security). You are usually eligible for SSDI if you have earned 20 credits out of the past 40 quarters. SSI, on the other hand, is awarded based on financial need. SSI is not dependent upon prior work contributions and credit. SSI is awarded to those who make less than about $1400 monthly in income.