*admin edit* Since Rich stated that he gets "depressed" when he doesn't hear anything from SSA, he has every right to contact them. The reason a person would do so, depending on how strong they feel about their particular case (and those with a 3 year review are reviewed in 3 years and not 5 or 7 years for a reason), would be simply because of this statement on the form:

"The information you furnish on this report is voluntary. However, if you do not provide the requested information, a decision based on the evidence in your case can result in a determination that your disability has ceased."

You are right about a backlog, but you never know, maybe the form did get lost in the mail. It is probably sitting on someone's desk and they will get to it when they get to it, but if it isn't on their desk and it hasn't been received and benefits are ceased, it would be a person's own fault for not following up.