From the Providence RI Journal:
Are you self-employed? If so, make sure you accurately report all your earnings on your federal income-tax return, and file those returns on time. Otherwise, you may not qualify for Social Security benefits later on.
Thatâ€™s because the Social Security Administration looks to your federal income-tax returns to find out how much youâ€™ve earned and whether youâ€™ve paid Social Security tax on those self-employment earnings.
See full article here