The "date disability condition started" box on a claim form is very important. It is impossible, however, for anyone to tell you what date to use without knowing all of the facts and circumstances of your claim. Another date that is very important is the "last day worked." You may want to have an experienced disability attorney look at your claim form before you file it. That attorney will likely want to see your medical records/reports from your doctors. The attorney will likely charge a fee for this service, but this is a fee well worth paying.