SSDI denials happen frequently, with many of them focused around minor issues: Missing paperwork, a technical error, etc. Even so, these denials can take so long that some studies claim thousands of people pass away as they await their decisions. This happens each and every year.
As an example of just how long this process can take, look at the story of a 60-year-old woman with fibromyalgia. She suffers from chronic pain. She also has depression, high blood pressure, pinched nerves, kidney disease and diabetes.
She applied for SSDI and got denied. She applied again and got denied again. As she explained, the letter they sent to her noted that she was not disabled.
After the second denial, she decided to appeal. That was in August of 2017. It took more than a year, until November of 2018, before they even heard her appeal. Even with that done, she had not been notified of the ruling -- which could just be yet another denial -- just before the new year in 2019.
The report on her experience said that about 800,000 Americans were waiting on the decisions from their appeals at that time. That's when they said that every year saw thousands pass away before those decisions were made.
This isn't to make you think that you should not apply or that you are just going to get denied. Rather, it just shows you how long and complicated this process can really be, even when you feel that it's clear you have a valid claim. Make sure you know what steps you should take.