Just booked in for a B service at 92,000 miles. The computer came up with extras in the form of air and fuel filters and spark plugs. Brake fluid had been done by MB dealer at last service. On checking my Service Book I see that the spark plugs were last done at 58,000 miles in 2006. What are the intervals for change of plugs? Can I legitimately ask the dealer to skip the plug change? They are offering me 40% discount on labour and 10% on parts as the car is over six years old, so the cost is £475 without the plugs, which seems OK and keeps my MobiloLife intact. Another £300 for the plugs though so I'm keen to avoid this if I can.