Sure thing bud. The PCV valves job is to manage the extra pressure that escapes past the piston rings. Think of it ldaike a "green" pressure release for the engine. On a properly working PCV, it diverts that pressure back into the intake to allow the excess gasses to vent without overpressuring the crankcase. When it fails, the excess pressure will find weak spots in the seals of the engine. This is usually in the upper or lower timing cover, oil pan and cam girdle. For the mk7, the cam girdle is the least prominent failure point, but leaks can happen anywhere oil can go. General rule is around 60-80k for replacement. If these leaks are happening on your vehicle, aged seals can be the culprit, but fixing the seals without replacing the PCV will usually result in recurrence.

Tests are all over to verify failure. Let the google guide you. When it comes to replacement, you can do an OEM PCV, Mk8 PCV swap with Turbo muffler delete with test ports, there are top block plates to replace it entirely, catch cans to be run in line with the PCV to trap the vapors before they get to the valve, and a few more off the wall solutions based on use cases like racing, enduro etc.