Replacement - Flame Oil trap on 2001 Volvo S80

My Volvo has l08,000 miles. How can you tell if the "flame oil trap" needs replacing without just taking a mechanics word?

Asked by for the 2001 Volvo S80
Generally they leak oil all over the front of the engine, but this requires replacing the seals (which is very common on this engine). If it is plugged they will recommend replacement, and this may also cause oil leaks or driveability issues.
Why are they recommending replacement? What led them to this conclusion?