What is the recommendation on when to change the lock cylinder before problems occur? Mileage, age of car? I've already replaced the cylinder on my 240D, but the 300SD with 150k miles still has the original as far as I know.

John

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Certified Registered Nurse Anesthetist (CRNA)
2002 F250 powerstroke with Plantdrive WVO conversion
1983 300SD 190K miles ,sold
2006 E320 CDI