Pics from a car with 67k miles on it, for example:
http://www.golfmk6.com/forums/showpost.php?p=2500784&postcount=39094
It does affect performance & drivability and/or will, but it's your car
i was getting misfires and check engine lights at 45k miles
had them cleaned and the shop said it wasn't even that bad.
they didn't think it would fix the problem. It did... get those
valves cleaned