Here are a few thoughts on institutional memory from a talk by Admiral Hyman G. Rickover.
When important decisions are not documented, one becomes dependent on individual memory, which is quickly lost as people leave or move to other jobs. In my work, it is important to be able to go back a number of years to determine the facts that were considered in arriving at a decision. This makes it easier to resolve new problems by putting them into proper perspective. It also minimizes the risk of repeating past mistakes.
I’ve never seen this done effectively. I’ve been part of business and non-profit organizations that kept good records, but I don’t recall anyone ever looking back through the records to review why a decision was made.
This is especially a challenge in software development where the myth of progress runs so strong. Newer is always better. The people before us were stupid, so why should we go back and read what they thought? Or maybe they weren’t stupid, but they were working with version 10.5 of FooBar. Now we’re up to version 11.2 and so everything has changed.