If you receive a denial letter from Social Security regarding your application for Social Security disability benefits, you must appeal that denial of benefits within 60 days.
Initial disability claims get denied for many reasons, and many denials have nothing to do with the merit of your disability claim. A common mistake made by claimants is that, instead of appealing a denied claim, they reapply again (and are denied again). Avoid that mistake! You will improve your chances by appealing. You will ultimately have a hearing with a U.S. Administrative Law Judge (ALJ). The hearing level is your best chance to have your claim for disability benefits granted.