TBH, I don't know. I think yearly review would be a good technique to try.
What I have done is added things over the years. It's not so hard when it's an entirely new thing. For example, we added a Wiki about a decade ago. That worked really well. I recently added checks to the lab database so that new stuff at least is in a consistent format... for a while. In my experience, the problem is less one of adding as much as deciding when to retire something or deciding whether it is worth fixing legacy structures.
elduvelle