The SSDI process for disability claims is also VERY long. My brother's took well over a year and he ended up using one of those lawyers that advertise on the TV to help you through the process. There's a built-in assumption in the process that you are denied the first time, too.

So, start now.

(On the bright side, if I can use that term, if you are approved, you get benefits retroactive to when you applied.)