This won't help you digging yourself out of the hole, but going forward using a prefix naming system and adding notes has helped us a lot in this area. We use a prefix like 'SYS - Search Name' for important searches that workflows, scripts, integrations, etc rely on. So even if it's old and potentially not executed in a while we know to think twice. We also use a prefix of 'AUD' for audit searches as described by Jacob. Between the note and prefix it can go a long way toward preventing yourself from being in the same position in another 3 years.
Edit: maybe obvious but the note should be used to describe the purpose of the search, who uses it, what it solves, etc