From the early 1980s....to around 2009....I was in the clearance-required situation, and a review had to occur every five years.
Other than spending near three hours filling out the form papers....I didn't ever think it was a big deal.
You'd wrap up the paperwork....some security guy would validate the first step, and then six to nine months would pass....with the review 'stamped' and a new five-year period approved.
At some point around 2006, I submitted my papers three months before it ran out. The security guy processed it and it went on.
Around six months....near the end of 2006, I asked for a status. Nothing came.
Two months passed, I asked for another status (now into Feb 2007). Nothing came.
By mid-summer, I was up to eleven months since submission (the longest ever for me). I asked....any problems? No.
Around four more month pass....so I'm up to 15 months since submission. Now they kinda admit.....they lost my paperwork. So everything had to be re-generated from scratch. I was at this point of a full year 'late'. The security folks basically wrote a waiver form (not wanting to discuss how they lost the paperwork).
Toward the very end of 2008....it finally came back approved.
Where my original paperwork went? Anyone's guess.