Social Security disability is extremely complex. The rules for applying and submitting evidence constantly changes. It is enough to leave even seasoned lawyers scratching their heads.
For example, it is difficult for attorneys to file initial claims for disability online because SSA sends back the application to the individual claimant. The application must be signed by the claimant and witnessed. This defeats the point of hiring a lawyer to "cut through the red tape." If the application isn't verified in a proscribed period of time, then the application lapses.
In order to combat this, I follow up with the client multiple times over the weeks after submitting an initial application.
Generally speaking, it is better to have a lawyer because lawyers can keep track of these things, pay attention to the deadlines, submit medical evidence and, most importantly, represent claimants at the hearing.
Following up and keeping records of everything are the best ways to deal with the vagaries of SSA.