At minimum each player should pass this level. If it doesn't it should be serviced. Very Good Check Level-5 Excellent. This player is most capable of perfectly correcting errors caused by manufacturing faults, scratches, etc. It is not uncommon to buy a CD player that does not pass Check Level-2.
CD players detorierate over time.
Protect your audio investment by detecting pickup defects early. Use it to determine when pickup adjustments are needed. Use it to check the adjustment effectiveness. Test your player especially prior to warranty expiration. For more on each of these points click here .