The U.S. Submarine Service had all sorts of metrics as to what a "drip", "slow leak", "fast leak", and "flooding" constisted of (water in the "boat" is not a good thing). I boiled it all down back when I served and apply it to my current DBA work.
"If you find it, it's a leak. If it finds you, it's flooding." 😉
Be prepared. Be proactive.
--Jeff Moden
Change is inevitable... Change for the better is not.